Avaliação da perda óssea alveolar em pacientes encaminhados à especialista em periodontia: estudo radiográfico

The aim of this study was to evaluate the mean of alveolar bone loss (%) in radiographies of patients referred to specialist for periodontal treatment. Full mouth series of periapical radiographies (paralelism technique) were used. A total of 9808 proximal surfaces in 4804 teeth of 213 patients (90 males and 123 females), mean age, 44.3 years, were assessed. The alveolar bone loss was measured in relation to root lenght expressed as an average similar to Schei 's technique (1959) without the use of ruler. The references used were the distances cement-enamel juntion (CEJ) - alveolar crest (AC) and CEJ- dental apex taken with a digimatic caliper. The results showed that the mean values of alveolar bone loss (%ABL) was 22.39%. Men showed higher mean values of %ABL than women; the %ABL increased with the age, but the difference among age groups was no statistical significant (p>0.05); the mean values of %ABL of distal surfaces was higher than mesial surfaces (p<0.01), ríght quadrants exhibited higher %ABL values than left quadrants (p<0.01); maxillary sites showed mean values of %ABL higher than mandibular sites; the highest mean values of %ABL was found in molar group, followed by incisor groups, and premolar group; the canine group exhibited lower mean values of %ABL; the differences among the groups was considered statitistically significant (p<0.01). lt was suggested the usage of this technique in the dentistry offices and radiological services for the patient 's documentation and assortment and for later comparison about alveolar bone level

Straight and angulated abutments in platform switching: influence of loading on bone stress by three-dimensional finite element analysis

PURPOSE: In view of reports in the literature on the benefits achieved with the use of platform switching, described as the use of an implant with a larger diameter than the abutment diameter, the goal being to prevent the (previously) normal bone loss down to the first thread that occurs around most implants, thus enhancing soft tissue aesthetics and stability and the need for implant inclination due to bone anatomy in some cases, the aim of this study was to evaluate bone stress distribution on peri-implant bone, by using three-dimensional finite element analysis to simulate the influence of implants with different abutment angulations (0 and 15 degrees) in platform switching. METHODS: Four mathematical models of an implant-supported central incisor were created with varying abutment angulations: straight abutment (S1 and S2) and angulated abutment at 15 degrees (A1 and A2), submitted to 2 loading conditions (100 N): S1 and A1-oblique loading (45 degrees) and S2 and A2-axial loading, parallel to the long axis of the implant. Maximum (σmax) and minimum (σmin) principal stress values were obtained for cortical and trabecular bone. RESULTS: Models S1 and A1 showed higher σmax in cortical and trabecular bone when compared with S2 and A2. The highest σmax values (in MPa) in the cortical bone were found in S1 (28.5), followed by A1 (25.7), S2 (11.6), and A2 (5.15). For the trabecular bone, the highest σmax values were found in S1 (7.53), followed by A1 (2.87), S2 (2.85), and A2 (1.47). CONCLUSIONS: Implants with straight abutments generated the highest stress values in bone. In addition, this effect was potentiated when the load was applied obliquely.

Avaliação da qualidade de vida dos pacientes submetidos a artroplastia total primária do quadril antes e após a cirurgia

Pós-graduação em Saúde Coletiva - FMB

Artroplastia total híbrida nacional em cães Portadores de displasia coxofemoral

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da qualidade de vida dos pacientes submetidos a artroplastia total primária do quadril antes e após a cirurgia

Pós-graduação em Saúde Coletiva - FMB

Artroplastia total híbrida nacional em cães Portadores de displasia coxofemoral

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Temporal modifications in bone following spinal cord injury in rats

Introduction: The aim of this study was to investigate the temporal modifications in bone mass, bone biomechanical properties and bone morphology in spinal cord injured rats 2, 4 and 6 weeks after a transection. Material and methods: Control animals were randomly distributed into four groups (n = 10 each group): control group (CG) - control animals sacrificed immediately after surgery; spinal cord-injured 2 weeks (2W) - spinal cord-injured animals sacrificed 2 weeks after surgery; spinal cord-injured 4 weeks (4W) - spinal cord-injured animals sacrificed 4 weeks after surgery; spinal cord-injured 6 weeks (6W) - spinal cord-injured animals sacrificed 6 weeks after surgery. Results: Biomechanical properties of the right tibia were determined by a threepoint bending test and injured animals showed a statistically significant decrease in maximal load compared to control animals. The right femur was used for densitometric analysis and bone mineral content of the animals sacrificed 4 and 6 weeks after surgery was significantly higher compared to the control animals and animals sacrificed 2 weeks after surgery. Histopathological and morphological analysis of tibiae revealed intense resorptive areas in the group 2 weeks after injury only. Conclusions: The results of this study show that this rat model is a valuable tool to investigate bone remodeling processes specifically associated with SCI. Taken together, our results suggest that spinal cord injury induced bone loss within 2 weeks after injury in rats.

Low Bone Mineral Density in Middle-Aged Breast Cancer Survivors: Prevalence and Associated Factors

Background: The aim of this study was to investigate the prevalence of low bone mineral density (BMD) and associated factors in middle-aged breast cancer survivors (BCS). Patients and Methods: A cross-sectional study was conducted with 70 BCS of 45-65 years of age undergoing complete oncology treatment. Logistic regression models were used to identify factors associated with low BMD (osteopenia and osteoporosis taken together as a single group). Results: The mean age of participants was 53.2 +/- 5.9 years. BMD was low at the femoral neck in 28.6% of patients and at the lumbar spine in 45.7%. Body mass index <= 30 kg/m(2) (adjusted odds ratio (OR) 3.43; 95% confidence interval (CI) 1.0-11.3) and postmenopausal status (OR adjusted 20.42; 95% CI 2.0-201.2) were associated with low BMD at the lumbar spine. Femoral neck measurements, age > 50 years (OR 3.41; 95% CI 1.0-11.6), and time since diagnosis > 50 months (OR adjusted 3.34; 95% CI 1.0-11.3) increased the likelihood of low BMD. Conclusion: These findings show that low BMD is common in middle-aged BCS. Factors were identified that may affect BMD in BCS and should be considered when implementing strategies to minimize bone loss in middle-aged women with breast cancer.

Bone mineral density in postmenopausal women with and without breast cancer

OBJECTIVE: The values of bone mineral density (BMD) were compared in postmenopausal women with and without breast cancer. METHODS: A cross-sectional study was conducted, including 51 breast cancer survivors (BCS) and 71 women without breast cancer, who were non-users of hormone therapy, tamoxifen, or aromatase inhibitors. BMD T-scores and measurements in grams per centimeter squared (g/cm²) were obtained at the femoral neck, trochanter, Ward's triangle, and lumbar spine. Osteopenia and osteoporosis were grouped and categorized as abnormal BMD. Unconditional logistic regression analysis was used to estimate the odds ratios (OR) of abnormal BMD values as measures of association, with 95% confidence intervals (CIs), adjusting for age, years since menopause, parity, and body mass index (BMI). RESULTS: The mean age of the women with and without breast cancer was 54.7 ± 5.8 years and 58.2 ± 4.8 years (p < 0.01), respectively. After adjusting for age, parity and BMI, abnormal BMD at the femoral neck (adjusted OR: 4.8; 95% CI: 1.5-15.4), trochanter (adjusted OR: 4.6; 95% CI: 1.4-15.5), and Ward's triangle (adjusted OR: 4.5; 95% CI: 1.5-12.9) were significantly more frequent in postmenopausal BCS than in women without breast cancer. Postmenopausal BCS had a significantly lower mean BMD at the trochanter (0.719 vs. 0.809 g/cm², p < 0.01) and at the Ward's triangle (0.751 vs. 0.805 g/cm², p = 0.03). CONCLUSION: The prevalence of abnormal BMD was higher in postmenopausal BCS than in postmenopausal women without breast cancer. Bone health requires special vigilance and the adoption of interventions should be instituted early to minimize bone loss in BCS.

Morse taper implants at different bone levels: a finite element analysis of stress distribution

AIM: To explore the biomechanical effects of the different implantation bone levels of Morse taper implants, employing a finite element analysis (FEA). METHODS: Dental implants (TitamaxCM) with 4x13 mm and 4x11 mm, and their respective abutments with 3.5 mm height, simulating a screwed premolar metal-ceramic crown, had their design performed using the software AnsysWorkbench 10.0. They were positioned in bone blocks, covered by 2.5 mm thickness of mucosa. The cortical bone was designed with 1.5 mm thickness and the trabecular bone completed the bone block. Four groups were formed: group 11CBL (11 mm implant length on cortical bone level), group 11TBL (11 mm implant length on trabecular bone level), group 13CBL (13mm implant length on cortical bone level) and group 13TBL (13 mm implant length on trabecular bone level). Oblique 200 N loads were applied. Von Mises equivalent stresses in cortical and trabecular bones were evaluated with the same design program. RESULTS: The results were shown qualitatively and quantitatively by standard scales for each type of bone. By the results obtained, it can be suggested that positioning the implant completely in trabecular bone brings harm with respect to the generated stresses. Its implantation in the cortical bone has advantages with respect to better anchoring and locking, reflecting a better dissipation of the stresses along the implant/bone interfaces. In addition, the search for anchoring the implant in its apical region in cortical bone is of great value to improve stabilization and consequently better stress distribution. CONCLUSIONS: The implant position slightly below the bone in relation to the bone crest brings advantages as the best long-term predictability with respect to the expected neck bone loss.

Costruzione di uno scaffold vascolarizzato per la chirurgia ortopedica

Specific aims The aim is to improve the treatment of the bone losses at the metacarpal bones level (both diaphysis and epiphysis) combining microsurgery, tissue engineering and biomaterials, so to minimize the donor side morbidity and optimize healing and outcomes. Methods Pre-operative controlateral X-ray or 3-D CT to allow custom-made HA scaffolds. Cement as temporary spacer in acute lesion and monitoring of infective risks. Treatment of the bone loss recurring to pre-fabricated or custom-made HA scaffolds, adding platelet gel or growth factor OP1. Stable synthesis. Control group with auto/omografts. Outcome indices: % of bone-union; finger TAM, Kapandji, DASH score; NMR and Scintigraphy at 180 days for revascularisation and bio-substitution of the scaffold. Preliminary results The authors just treated 6 patients, 4 males and 2 females, with an average age of 38.5 yrs, affected by segmental bone losses at the hand and wrist, recurring to pre-fabricated not vascularised scaffolds. In all cases the synthesis was performed with angular stability plates and a stable synthesis achieved. All patients have been controlled at a mean follow-up of 10.5 months (from 2 to 16 ). In all case but one the bone-scaffold osteo-integration was achieved at an average of 38 days at the hand, and 46 days at the wrist. The outcome studies, according to the DASH score, finger TAM, and Kapandji, were good and excellent in 5 cases, poor in one.

Biomimetic Materials for Biomedical Applications

Objects with complex shape and functions have always attracted attention and interest. The morphological diversity and complexity of naturally occurring forms and patterns have been a motivation for humans to copy and adopt ideas from Nature to achieve functional, aesthetic and social value. Biomimetics is addressed to the design and development of new synthetic materials using strategies adopted by living organisms to produce biological materials. In particular, biomineralized tissues are often sophisticate composite materials, in which the components and the interfaces between them have been defined and optimized, and that present unusual and optimal chemical-physical, morphological and mechanical properties. Moreover, biominerals are generally produced by easily traceable raw materials, in aqueous media and at room pressure and temperature, that is through cheap process and materials. Thus, it is not surprising that the idea to mimic those strategies proper of Nature has been employed in several areas of applied sciences, such as for the preparation of liquid crystals, ceramic thin films computer switches and many other advanced materials. On this basis, this PhD thesis is focused on the investigation of the interaction of biologically active ions and molecules with calcium phosphates with the aim to develop new materials for the substitution and repair of skeletal tissue, according to the following lines: I. Modified calcium phosphates. A relevant part of this PhD thesis has been addressed to study the interaction of Strontium with calcium phosphates. It was demonstrated that strontium ion can substitute for calcium into hydroxyapatite, causing appreciable structural and morphological modifications. The detailed structural analysis carried out on the nanocrystals at different strontium content provided new insight into its interaction with the structure of hydroxyapatite. At variance with the behaviour of Sr towards HA, it was found that this ion inhibits the synthesis of octacalcium phosphate. However, it can substitute for calcium in this structure up to 15 atom %, in agreement with the increase of the cell parameters observed on increasing ion concentration. A similar behaviour was found for Magnesium ion, whereas Manganese inhibits the synthesis of octacalcium phosphate and it promotes the precipitation of dicalcium phosphate dehydrate. It was also found that Strontium affects the kinetics of the reaction of hydrolysis of α-TCP. It inhibits the conversion from α-TCP to hydroxyapatite. However, the resulting apatitic phase contains significant amounts of Sr2+ suggesting that the addition of Sr2+ to the composition of α-TCP bone cements could be successfully exploited for its local delivery in bone defects. The hydrolysis of α-TCP has been investigated also in the presence of increasing amounts of gelatin: the results indicated that this biopolymer accelerates the hydrolysis reaction and promotes the conversion of α-TCP into OCP, suggesting that its addition in the composition of calcium phosphate cements can be employed to modulate the OCP/HA ratio, and as a consequence the solubility, of the set cement. II. Deposition of modified calcium phosphates on metallic substrates. Coating with a thin film of calcium phosphates is frequently applied on the surface of metallic implants in order to combine the high mechanical strength of the metal with the excellent bioactivity of the calcium phosphates surface layers. During this PhD thesis, thank to the collaboration with prof. I.N. Mihailescu, head of the Laser-Surface-Plasma Interactions Laboratory (National Institute for Lasers, Plasma and Radiation Physics – Laser Department, Bucharest) Pulsed Laser Deposition has been successfully applied to deposit thin films of Sr substituted HA on Titanium substrates. The synthesized coatings displayed a uniform Sr distribution, a granular surface and a good degree of crystallinity which slightly decreased on increasing Sr content. The results of in vitro tests carried out on osteoblast-like and osteoclast cells suggested that the presence of Sr in HA thin films can enhance the positive effect of HA coatings on osteointegration and bone regeneration, and prevent undesirable bone resorption. The possibility to introduce an active molecule in the implant site was explored using Matrix Assisted Pulsed Laser Evaporation to deposit hydroxyapatite nanocrystals at different content of alendronate, a bisphosphonate widely employed in the treatments of pathological diseases associated to bone loss. The coatings displayed a good degree of crystallinity, and the results of in vitro tests indicated that alendronate promotes proliferation and differentiation of osteoblasts even when incorporated into hydroxyapatite. III. Synthesis of drug carriers with a delayed release modulated by a calcium phosphate coating. A core-shell system for modulated drug delivery and release has been developed through optimization of the experimental conditions to cover gelatin microspheres with a uniform layer of calcium phosphate. The kinetics of the release from uncoated and coated microspheres was investigated using aspirin as a model drug. It was shown that the presence of the calcium phosphate shell delays the release of aspirin and allows to modulate its action.

Valutazione del rilascio ionico in pazienti portatori di protesi di rivestimento d'anca BHR: confronto a lungo termine con artroplastica totale d'anca metallo-metallo

Lo scopo di questo studio è stato quello di determinare se a lungo termine le concentrazioni sieriche di ioni nei pazienti con protesi di rivestimento d’anca metallo-metallo (MOM-HR, metal-on-metal hip resurfacing) fossero differenti da quelle valutate nei pazienti con protesi totale d’anca metallo-metallo e testa del diametro di 28 mm (MOM-THA, metal-on-metal total hip arthroplasty); inoltre è stato valutato se le concentrazioni ioniche fossero al di sopra dei valori di riferimento e se fosse possibile stabilire l’esistenza di una relazione tra sesso e concentrazioni di ioni con riferimento al tipo di impianto. Il gruppo MOM-HR era costituito da 25 pazienti mentre il gruppo MOM-THA era di 16 pazienti. Per poter ricavare i valori di riferimento sono stati reclutati 48 donatori sani. La misurazione delle concentrazioni degli ioni cobalto (Co), cromo (Cr), nickel (Ni) e molibdeno (Mo) è stata effettuata utilizzando la spettrofotometria ad assorbimento atomico su fornace di grafite. A parte il Ni, le concentrazioni di ioni nei pazienti con MOM-HR erano più elevate rispetto ai controlli. Il rilascio di ioni Cr e Co nei pazienti con MOM-HR è risultato superiore rispetto ai soggetti con MOM-THA. Da un’analisi basata sul sesso, è emerso che nelle femmine con MOM-HR i livelli di ioni Cr e Co sono risultati significativamente aumentati rispetto alle femmine con MOM-THA. Indipendentemente dal tipo di impianto, gli accoppiamenti metallo-metallo (MOM) producono concentrazioni di ioni metallici significativamente più alte a follow-up a lungo termine rispetto a quelle osservate nei soggetti sani. Un fattore che deve essere attentamente considerato nella scelta dell’impianto, e in particolar modo nei soggetti giovani, è il cospicuo rilascio di ioni Cr e Co nella popolazione femminile con MOM-HR.

Sindrome da insensitività completa agli androgeni e massa ossea. Valutazione basale e longitudinale dopo oltre 12 mesi di terapia estrogenica

L’osso è un tessuto target per estrogeni ed androgeni ma l’azione singola e la sinergia tra i due non sono compresi interamente. Le donne affette da Sindrome da Insensititvità Completa agli Androgeni (CAIS) hanno un cariotipo 46XY ma presentano una completa inattività del recettore degli androgeni. Nello studio abbiamo valutato la densità minerale ossea (BMD) in un gruppo di donne adulte CAIS sottoposte a gonadectomia al momento della prima visita e dopo almeno 12 mesi di terapia estrogenica. Il principale obiettivo è stato di valutare se, nelle donne CAIS, una ottimale estrogenizzazione fosse sufficiente a mantenere/ripristinare una adeguata BMD. 24 donne CAIS sono state sottoposte a DXA lombare e femorale all'arruolamento nello studio (t1), dopo terapia estrogenica di 12mesi(t2) e oltre (t>2). Sono state valutate: BMD(g/cm2) e Zscore lombare e femorale (a t1,t2 e t>2) E’ stato considerato se fossero rilevanti l’essere (gruppo1) o meno (gruppo 2) in terapia ormonale al t1 e l’età della gonadectomia. Risultati: Al t1 BMD e Zscore lombari e femorale erano significativamente ridotti rispetto alla popolazione controllo nel campione totale (lombare 0,900+0,12; -1,976+0,07, femorale 0,831 + 0,14; -1,385+0,98), nel gruppo 1 (lombare 0,918+0,116;-1,924+0,79, femorale 0,824+0,13;-1,40+1,00) e nel gruppo 2 (lombare 0.845+0,11 -2,13+1,15, femorale 0,857+0,17;-1,348+1,05) Al t2 e t>2 la BMD lombare è risultata significativamente aumentata (p=0,05 e p=0,02). Zscore lombare, BMD e Zscore femorale non hanno dimostrato variazioni significative. L’aver effettuato la gonadectomia in età post puberale è associato a Zscore lombare e femorale più elevati al t1. Nelle donne CAIS la terapia estrogenica è indispensabile per prevenire un'ulteriore perdita di BMD ma, da sola, non sembra in grado di ripristinare normali valori di BMD.I risultati del nostro studio supportano la tesi che gli androgeni, mediante l’azione recettoriale, abbiano un' azione diretta nel raggiungere e mantenere la BMD.

Finite element modeling of flow/compression-induced deformation of alginate scaffolds for bone tissue engineering

Trauma or degenerative diseases such as osteonecrosis may determine bone loss whose recover is promised by a "tissue engineering“ approach. This strategy involves the use of stem cells, grown onboard of adequate biocompatible/bioreabsorbable hosting templates (usually defined as scaffolds) and cultured in specific dynamic environments afforded by differentiation-inducing actuators (usually defined as bioreactors) to produce implantable tissue constructs. The purpose of this thesis is to evaluate, by finite element modeling of flow/compression-induced deformation, alginate scaffolds intended for bone tissue engineering. This work was conducted at the Biomechanics Laboratory of the Institute of Biomedical and Neural Engineering of the Reykjavik University of Iceland. In this respect, Comsol Multiphysics 5.1 simulations were carried out to approximate the loads over alginate 3D matrices under perfusion, compression and perfusion+compression, when varyingalginate pore size and flow/compression regimen. The results of the simulations show that the shear forces in the matrix of the scaffold increase coherently with the increase in flow and load, and decrease with the increase of the pore size. Flow and load rates suggested for proper osteogenic cell differentiation are reported.