Comparação de diferentes metodologias para análise histométrica de implantes: estudo em ratos / Comparison of different methodologies for histometric analysis of implant. Study in rat

Introdução: Diferentes metodologias tem sido utilizadas para avaliação histológica da osseointegração, levando a diferentes resultados. Objetivo: O objetivo é comparar diferentes metodologias de análise histomorfométrica da osseointegração de implantes com diferentes superfícies, instalados em tíbias de ratos. Material e método: 24 ratos foram aleatoriamente divididos em 3 grupos (n = 8) para a instalação dos implantes. Esses grupos foram divididos de acordo com o tipo de implante instalado na tíbia: Grupo Hidrofílico - HFL (instalação de implante com superfície modificada por jateamento de óxidos e ataque ácido e mantida em solução de cloreto de sódio), Grupo Hidrofóbico - HFB (instalação de implante com superfície modificada por jateamento de óxidos e ataque ácido) e Grupo Usinado - U (instalação de implante com superfície usinada). No período de 45 dias após os procedimentos cirúrgicos de instalação dos implantes, os animais foram submetidos à eutanásia, e as tíbias foram removidas, sendo realizado o processamento histológico para amostras não descalcificadas. Após a obtenção das lâminas, foi realizada a análise histomorfométrica para avaliar as porcentagens de contato osso-implante (% BIC) e da área óssea entre as espiras (% BBT). As mensurações foram realizadas em duas diferentes regiões: 1) as roscas do implante na região do osso cortical e 2) todas as roscas do implante inseridas no osso (cortical e medular). A análise estatística foi feita por meio de ANOVA One-Way, seguida pelo teste de Tukey para análise inferencial dos dados. Resultado: Quando o BIC e o BBT foram analisados de forma independente nas regiões cortical e trabecular/total, observou-se uma diferença no comportamento histológico dos implantes de acordo com o tratamento de superfície. Os implantes HFL apresentaram BIC (%) trabecular 16,85% maior (p = 0,02) do que os implantes HFB e 26,12% maior (p ≤ 0,0001) do que os implantes usinados. Contudo, a região cortical de todos os grupos apresentou valores de BIC cortical significativamente maiores ao redor dos implantes, independentemente da superfície. Conclusão: Os resultados obtidos demonstraram que a formação óssea peri-implantar foi superior nas análises realizadas apenas em osso cortical, se comparados aos valores obtidos na mensuração total (osso cortical somado ao medular). Também foi possível observar que, dentro da mesma superfície, os valores de BIC (%) foram superiores em osso cortical. Em relação às limitações do estudo, pode-se concluir que diferentes metodologias de análise histométrica da osseointegração ao redor de diferentes superfícies de implantes instalados em tíbias de ratos podem interferir nos resultados de osseointegração, independentemente da superfície analisada.

Introduction: Different methodologies were used for histological evaluation of osseointegration, leading to different results. Objective: The objective is to compare different methodologies for histomorphometric analysis of the osseointegration of implants with different surfaces, installed in rat tibias. Material and method: Twenty-four rats were randomly divided into 3 groups (n=8) for implant installation. These groups were divided according to the type of implant that will be installed in the tibia: Hydrophilic Group (installation of an implant with a surface modified by oxide blasting and acid attack and maintained in a sodium chloride solution), Hydrophobic Group (installation of an implant with surface modified by oxide blasting and acid attack) and Machined Group (implant installation with machined surface). Within 45 days after the surgical procedures to install the implants, the animals were euthanized and the tibias were removed, and histological processing was carried out for non-decalcified samples. After obtaining the slides, histomorphometric analysis was performed to evaluate the percentages of bone-implant contact (%BIC) and the bone area between the turns (%BBT). Measurements were carried out in two different regions: 1) the implant threads in the cortical bone region and 2) all implant threads inserted into the bone (cortical and medullary). Statistical analysis was performed using One-Way ANOVA followed by Tukey's test for inferential data analysis. Result: The BIC and BBT were analyzed independently in the cortical and trabecular/total regions, a difference was observed in the histological behavior of the implants according to the surface treatment. HFL implants showed trabecular BIC (%) 16.85% higher (p=0.02) than HFB implants and 26.12% higher (p≤0.0001) than machined implants. However, the cortical region of all groups showed significantly higher cortical BIC values around the implants, regardless of the surface. Conclusion: the results obtained demonstrated that peri-implant bone formation was superior in analyzes carried out only on cortical bone, compared to the values obtained in the total measurement (cortical bone plus medullary bone). It was also possible to observe that, even within the same surface, the BIC(%) values were higher in cortical bone. Within the limitations of the study, it can be concluded that different methodologies for histometric analysis of osseointegration around different surfaces of implants installed in rat tibias can interfere with the results of osseointegration regardless of the surface analyzed

Equine Stomach Development in the Foetal Period of Prenatal Life-A Histological and Histometric Study.

Histological and morphometrical analysis of the stomach wall was performed during the foetal period divided into three age groups (4th-11th month of gestation). The material was taken from non-glandular (the blind ventricular sac) and glandular parts (the plicated edge margin/cardiac part, the body of stomach and the pyloric part) of the stomach. It was preserved and prepared according to the standard protocol. The histological slides were stained (H-E, Masson-Goldner and PAS). The analyses were performed using the light microscope. All measurements were statistically elaborated. The crown-rump length growth rate was estimated as isometric. The blind ventricular sac growth rate was lower than CRL (negative allometric) and the partition of stomach mucosa into non-glandular and glandular part occurred in the 1st age group. The plicated edge margin/cardiac part and the pyloric part shoved similar tendencies. Only the body of stomach demonstrated a higher growth rate than CRL (positive allometric), which can be explained due to the strongest development of fundic glands. Moreover, comparing the adult reference group to the three parts of the foetal period, all metric values were lower than those achieved prenatally. The blind ventricular sac was covered with the multiple plane epithelium. The glandular parts of stomach that formed the superficial concave areas were covered with the simple columnar epithelium in the 1st age group, which developed to the cardiac, fundic, and pyloric glands in the 2rd and 3rd age groups. The propria mucosae was built with the mesenchyme, which differentiated later to the loose connective tissue. The muscular layer of mucosa was not clearly distinguishable in the 1st age group. The muscular layer of the stomach wall was formed with myoblasts in the 1st age group and later in the 2nd and the 3rd age groups built with fusiform myocytes divided into internal and external layers. The non-differentiated cells of glandular epithelium transformed into the parietal and chief cells. The first were visible in the gastric glands of the 2nd age group. Both of them were present in the 3rd age group gastric mucosa. The PAS staining proved a moderate PAS-positive reaction in the 2rd age group, while it was estimated as intense Pas-positive in the gastric glands in the 3rd age group and was comparable to postnatal observation (the adult reference group).

Platelet-Derived Growth Factor-Modulated Guided Tissue Regeneration with a Bioresorbable Membrane in Class III Furcation Defects: A Histometric Study in the Monkey.

It was the aim of this study to histometrically evaluate guided tissue regeneration (bioresorbable membrane plus bone mineral) (GTR) with or without platelet-derived growth factor (PDGF) in two different types of class III furcation defects (small keyhole defects and horizonal defects) in monkeys. In six cynomolgus monkeys, two types of class III furcation defects were created and allowed to chronify for 5 months in mandibular first and second molars. After a hygiene program the molars were assigned to GTR group (collagen membrane plus bovine bone mineral), PDGF group (collagen membrane plus bovine bone mineral plus PDGF), or negative control group (flap reposition only). Histologic sections were made after 7 months of healing and descriptive statistics were provided from the histometric parameters. Postoperative healing was uneventful despite marginal membrane exposures in the GTR and PDGF group. Bone regeneration of 23-35% of the original defect area was found in the two treatment groups. In none of the evaluated key parameters (formation of bone, root cementum, connective tissue, or epithelium) differences were detected between GTR and PDGF groups. However, the negative control teeth exhibited better bone regeneration than the treatment groups. The type of class III defect did not influence the regenerative outcome. Within the limits of this study PDGF was not able to enhance the histologic regeneration of class III furcation areas in monkeys compared to bone mineral enhanced GTR treatment regardless of the defect configuration. Membrane exposure during early healing might have influenced these outcomes.

De novo bone formation around implants with a surface based on a monolayer of multi-phosphonate molecules. An experimental in vivo investigation.

OBJECTIVES: The purpose of this experimental in vivo investigation was to evaluate the influence of modifying the implant surface by adding a monolayer of multi-phosphonate molecules on the de novo bone formation and osseointegration. MATERIAL AND METHODS: The study was designed as an animal preclinical trial with intra-animal control and two healing periods, 2 and 8 weeks, to compare implants with an identical macro-design but with two different surfaces. Eight female Beagle dogs participated in the study. Control implants had a moderately rough surface combining sandblasting and acid etching; test implants had an additional monophosphonate layer covalently bonded to titanium. Histologic and radiographic (micro-CT) outcome variables were evaluated. RESULTS: The first bone-to-implant contact (fBIC) was located more coronally for the test implants at the first (0.065 mm (95% CI = -0.82, 0.60)) and second healing milestones (0.17 mm (95% CI = -0.9, 0.55)). Most coronal BIC of the test implants displayed a higher percentage of osseointegration, +6.33% and +13.38% after 2 and 8 weeks, respectively; however, the differences were not statistically significant. The micro-CT examination did not show any BIC difference. CONCLUSIONS: The monophosphonate layer coating demonstrated clinical, histological, and radiographic results similar to the control surface.

Experimental peri-implantitis around titanium implants with a chemically modified surface with a monolayer of multi-phosphonate molecules: a preclinical in vivo investigation.

OBJECTIVES: The purpose of this experimental in vivo investigation was to evaluate the influence of modifying the implant surface by adding a monolayer of multi-phosphonate molecules on the development of experimental peri-implantitis. MATERIAL AND METHODS: Eight beagle dogs received 5 tests and 5 control implants each following a split-mouth design 3 months after premolar and molar extraction. On the most mesial implant of each side, a 3-mm buccal dehiscence was artificially created. Experimental peri-implantitis was induced by silk ligatures over a 4-month period; after ligature removal, peri-implantitis was left to progress for another 4 months without plaque control. Clinical, histological, and radiographic outcomes were evaluated. RESULTS: Radiographically, both implant groups showed a similar bone loss (BL) at the end of the induction and progression phases. BL measured on the histological sections of the test and control groups was 3.14 ± 0.42 mm and 3.26 ± 0.28 mm, respectively; the difference was not statistically significant (p > 0.05). The remaining buccal bone to implant contact (bBIC) percentage of the test and control groups was 59.38 ± 18.62 and 47.44 ± 20.46%, respectively; the difference, however, was not statistically significant (p > 0.05). Bone loss observed at dehiscent sites compared to non-dehiscent ones showed no statistically significant difference (p > 0.05). CONCLUSIONS: Addition of a monophosphonate layer to a moderately rough implant surface did not affect development of experimental peri-implantitis. CLINICAL RELEVANCE: Influence of implant surface on peri-implantitis may condition implant selection by the clinician, especially on patients with disease risk factors. In that sense, monophosphate layer implants do not show higher peri-implantitis risk than control implants.

The adjunctive effect of rhBMP-2 on the regeneration of peri-implant bone defects after experimental peri-implantitis.

OBJECTIVES: The aim was to evaluate the degree of bone regeneration and re-osseointegration attained when combining a xenogeneic bone replacement graft plus rhBMP-2 and a collagen membrane in ligature-induced peri-implantitis osseous defects in dogs. MATERIAL AND METHODS: Thirty-six implants were placed in a total of 6 Beagle dogs, 3 months after tooth extraction. Once experimental peri-implantitis was induced, defects were randomly allocated into two treatment groups: in the test group guided bone regeneration was applied using de-proteinized bovine bone mineral with 10% collagen soak loaded with rhBMP2 covered with a natural collagen membrane. In the control group, the same scaffold and membrane were used but saline was used to soak the grafting material. After a period of 8 weeks of healing, a submerged environment clinical measurements were taken and histological outcomes were evaluated once the animals were euthanized. Histological bone defect regeneration (BR) was considered as the primary outcome variable, and dog was selected as the unit of analysis. RESULTS: Partial defect resolution was observed in both treatment groups. The histometric analysis showed a higher degree of bone regeneration for the test group, although differences were not statistically significant, both in terms of histological bone gain and percentage of re-osseointegration. CONCLUSIONS: (a) The addition of rhBMP2 to a bovine xenograft/collagen vehicle carrier failed to provide a significant added value in terms of bone regeneration or re-osseointegration, (b) partial re-osseointegration of a previously contaminated surface was achieved, although (c) a complete defect resolution and re-osseointegration to the level previous to the induction of the disease failed to occur in any of the treatment groups.

Epithelial tissue thickness improves optical coherence tomography's ability in detecting oral cancer.

BACKGROUND: OCT is a non-invasive imaging technique that enables the measurement of epithelial thickness and architectural changes, which can help in the diagnosis of pre-cancerous and cancerous lesions. The purpose of the study was to assess whether epithelial tissue thickness improves optical coherence tomography's ability in detecting oral cancer. PATIENTS AND METHODS: Surgically resected oral margins from 60 patients diagnosed with oral squamous cell carcinoma were subjected to OCT. Three OCT measurements (immediate, 1 h and 24 h post-resection) were conducted per resected tissue specimen to look at the effect of saline and formalin on the specimen and its effect on the reproducibility of the OCT. OCT was, then, used to measure the epithelial tissue thickness in cancer-free and cancer-involved margins in eight oral anatomical locations. This data was, then, combined with architectural changes data to calculate the sensitivity and specificity. RESULTS: An overall of 189 cancer-free margins and 51 cancer-involved margins had their epithelial thickness measured using OCT and compared to histopathology. With regards to the validity of the OCT and histopathological measurements, epithelial thickness showed good correlation between different readings at all oral sites. With regards to the reproducibility of the OCT measurements, the mean epithelial thickness for all measurements at first (immediate) and second (1 h post-resection - saline preserved) measurements was not significantly different. Underestimation of the epithelial depth in cancer-free margins was 20 µm, while in the cancer-involved margins was 10 µm. Combining data from architectural changes and epithelial thickness, a sensitivity of 92% and a specificity of 94% was achieved. CONCLUSION: Oral epithelium measurements using OCT were valid compared to those made with gold standard pathology. Measurements made using OCT was also reproducible with minor underestimation. Epithelial thickness, combined with architectural changes, led to high accuracy in differentiating between cancer-free and cancer-involved margins.

Ridge alterations after implant placement in fresh extraction sockets or in healed crests: An experimental in vivo investigation.

OBJECTIVES: To study the early and late bone healing around implants placed according to a flapless immediate (test) or flapped delayed (control) implant surgical protocol. MATERIALS AND METHODS: In eight beagle dogs, immediate and delayed implants were placed. Test and control implants were randomly assigned, and horizontal and vertical bone remodelling, as well as bone-to-implant contact (BIC), were assessed with histology at 2 and 8 weeks. Teeth were used as negative controls. RESULTS: Similar results were attained in the two groups when the vertical resorption of the buccal bone crest was evaluated (approximately 0.5 mm). On the other hand, a marked horizontal buccal bone resorption was observed. Immediate implants attained a thinner buccal bone crest as compared to the delayed implant and the tooth. De novo bone formation on the implant surface appeared to be more pronounced at delayed sites at 2 weeks, whereas at 8 weeks, no difference in BIC was observed. CONCLUSIONS: Ridge alterations occurred at both implant placement protocols, with similar limited amounts of vertical buccal bone reduction and a pronounced horizontal bone reduction. The process of horizontal bone remodelling differed between the two surgical protocols.

Soft tissue substitutes to increase gingival thickness: Histologic and volumetric analyses in dogs.

OBJECTIVES: To evaluate the histologic and volumetric changes of gingival tissues following grafting with collagen-based matrices at labial aspect of teeth in canines. MATERIALS AND METHODS: Gingival augmentation was performed in the mandibular incisor area using two types of xenogeneic cross-linked collagen matrices (CCMs), bovine CCM for BCCM group and porcine CCM for PCCM group, whereas the contralateral sides remained untreated (B-control group and P-control group). Descriptive histology, histometric and volumetric analyses were performed after 12 weeks. For statistical comparison between each test group and respective control group, paired t test was used for histometric analysis, and repeated-measured analysis of variance was used for volumetric analysis (p < 0.05). RESULTS: An increased number of rete pegs and an enhanced formation of new blood vessels were observed at both grafted sites compared to the corresponding control sites. There was statistically significant gain of horizontal thickness only in BCCM group (1.36 ± 0.27 mm vs. 1.26 ± 0.34 mm; p < 0.05) compared to the B-control groups. CONCLUSION: BCCM was effective for gingival augmentation in terms of horizontal thickness at the labial aspect of teeth at 12 weeks post-surgery.

Polydopamine deposition with anodic oxidation for better connective tissue attachment to transmucosal implants.

BACKGROUND AND OBJECTIVE: Nowadays, most designs for the transmucosal surface of implants are machined-smooth. However, connective tissue adhered to the smooth surface of an implant has poor mechanical resistance, which can render separation of tissue from the implant interface and induce epithelial downgrowth. Modification of the transmucosal surface of implants, which can help form a good seal of connective tissue, is therefore desired. We hypothesized that anodic oxidation (AO) and polydopamine (PD) deposition could be used to enhance the attachment between an implant and peri-implant connective tissue. We tested this hypothesis in the mandibles of Beagle dogs. MATERIAL AND METHODS: AO and PD were used to modify the transmucosal region of transmucosal implants (implant neck). The surface microstructure, surface roughness and elemental composition were investigated in vitro. L929 mouse fibroblasts were cultured to test the effect of PD on cell adhesion. Six Beagle dogs were used for the in vivo experiment (n = 6 dogs per group). Three months after building the edentulous animal model, four groups of implants (control, AO, PD and AO + PD) were inserted. After 4 months of healing, samples were harvested for histometric analyses. RESULTS: The surfaces of anodized implant necks were overlaid with densely distributed pores, 2-7 µm in size. On the PD-modified surfaces, N1s, the chemical bond of nitrogen in PD, was detected using X-ray photoelectron spectroscopy. L929 developed pseudopods more quickly on the PD-modified surfaces than on the surfaces of the control group. The in vivo experiment showed a longer connective tissue seal and a more coronally located peri-implant soft-tissue attachment in the AO + PD group than in the control group (P < .05). CONCLUSION: The modification of AO + PD on the implant neck yielded better attachment between the implant and peri-implant connective tissue.

Histometric analysis and topographic characterization of cp Ti implants with surfaces modified by laser with and without silica deposition.

Biologic behavior of the bone tissue around implants with four different surfaces was evaluated. The surfaces were: modified by laser (LS); modified by laser with sodium silicate deposition (SS); and commercially available surfaces modified by acid etching (AS) and machined surface (MS). Topographic characterization of the surfaces was performed by scanning electron microscopy (SEM)- energy dispersive X-ray spectrometry (EDX) before experimental surgery. Thirty rabbits received 60 implants in their right and left tibias, 1 implant of each surface being placed in each tibia. The analyzed periods were 4, 8, and 12 weeks postoperatively. Histometric analysis was performed evaluating bone interface contact (BIC) and bone area (BA). The results obtained were submitted to the analysis of variance and the Tukey t-test. The elemental mapping was evaluated by means of SEM at 4 weeks postoperatively. The topographic characterization showed differences between the analyzed surfaces. Generally, the BIC and BA of LS and SS implants were statistically higher than those of AS and MS in most of the analyzed periods. Elemental mapping showed high peaks of calcium and phosphorous in all groups. Based on the present methodology, it may be concluded that experimental modifications LS and SS accelerated the stages of the bone tissue repair process around the implants, providing the highest degree of osseointegration.

Estudo comparativo in vivo de implantes Ti-cp com superfícies comerciais e modificadas por laser sem e com depósito de sílica: análises biomecânica, topográfica e histométrica / Comparative in vivo study of cp-Ti implants with commercially available surfaces and those modified by laser, with and without silica deposition: biomechanical, topographic and histometric analyses

Proposição: O objetivo deste estudo foi comparar o comportamento biológico e mecânico do tecido ósseo ao redor de implantes de superfícies comerciais modificada por condicionamento ácido (SA), e usinada (SU), com implantes de superfícies experimentais modificada por laser (SL), e modificada por laser com depósito de sílica (SS), empregando-se as análises biomecânica, topográfica e histométrica. Material e Métodos: Trinta coelhos receberam 120 implantes de 3,75x10mm em suas tíbias direita e esquerda, sendo dois implantes de cada superfície por tíbia. O implante localizado mais superior, instalado na metáfise tibial foi utilizado para o ensaio biomecânico, descrito no capítulo I; e o implante localizado abaixo deste, instalado na epífise tibial foi utilizado para o estudo histométrico, descrito no capítulo II. A morfologia das superfícies dos implantes foi analisada por microscopia eletrônica de varredura (MEV), e por espectroscopia de energia dispersiva de raios X (EDS) antes, e após 4 semanas de implantação e remoção por torque reverso. Medidas de rugosidade e secção transversal foram obtidas. Após períodos de 4, 8, e 12 semanas realizou-se o ensaio biomecânico, e após os animais sofreram eutanásia. As peças do implante localizado na epífise tibial foram levadas ao micrótomo para corte sem descalcificação. A análise histométrica foi realizada empregando-se microscopia óptica. Foi mensurada a extensão linear de contato entre osso e implante (ELCOI), e a área óssea (AO). Uma lâmina de cada superfície do período de 4 semanas foi metalizada para realização da análise do mapeamento elementar por MEV-EDS. Resultados: A caracterização topográfica mostrou diferenças entre as superfícies analisadas, e os valores de rugosidade média das SL e SS foram estatisticamente superiores (p<0,05) a SA. Na comparação estatística dos valores obtidos pelo ensaio biomecânico, verificou-se em 4 semanas que os implantes SS e SL apresentaram torque de remoção superior (p<0,05) aos SU e...

Purpose: The aim of this study was to compare the biologic and mechanical behavior of bone tissue around implants with commercially available surfaces, modified by acid etching (SA), and machined surfaces (SU), with the experimental surfaces modified by laser (SL), and modified by laser with silica deposition (SS), using biomechanical, topographic and histometric analyses. Materials and Methods: Thirty rabbits received 120 implants measuring 3,75x10mm in their right and left tibias, being two implants of each type of surface per tibia. The implant located in the uppermost position, inserted in the tibial metaphysis, was used for the biomechanical test, described in Chapter I; and the implant located below this, inserted in the tibial epiphysis, was used for the histometric study, described in Chapter II. The morphology of the implant surfaces was analyzed by scanning electron microscopy (SEM) and by energy dispersive X-ray spectrometry (EDS) before and after 4 weeks of implantation and removal by reverse torque. Mean roughness and cross-sectional measurements were obtained. After periods of 4, 8, and 12 weeks the biomechanical test was performed, and after this the animals were euthanized. The parts of the implant located in the tibial epiphysis were taken for cutting nondecalcified on a microtome. Histometric analysis was performed using an optical microscope. The bone interface contact (BIC), and the bone area (AO) were measured in percentages. A slide of each surface in the period of 4 weeks was metalized in order to analyze the element mapping by means of SEM-EDS. Results: The topographic characterization showed differences between the analyzed surfaces, and the mean roughness values of SL and SS were statistically higher (p<0,05) than those of SA. In the statistical comparison of the values obtained by the biomechanical test, it was verified that at 4 weeks the implants SS and SL presented a higher removal torque (p<0,05) than SU and SA. At 8 weeks the...

Estudo comparativo in vivo de implantes Ti-cp com superfícies comerciais e modificadas por laser sem e com depósito de sílica: análises biomecânica, topográfica e histométrica / Comparative in vivo study of cp-Ti implants with commercially available surfaces and those modified by laser, with and without silica deposition: biomechanical, topographic and histometric analyses

Proposição: O objetivo deste estudo foi comparar o comportamento biológico e mecânico do tecido ósseo ao redor de implantes de superfícies comerciais modificada por condicionamento ácido (SA), e usinada (SU), com implantes de superfícies experimentais modificada por laser (SL), e modificada por laser com depósito de sílica (SS), empregando-se as análises biomecânica, topográfica e histométrica. Material e Métodos: Trinta coelhos receberam 120 implantes de 3,75x10mm em suas tíbias direita e esquerda, sendo dois implantes de cada superfície por tíbia. O implante localizado mais superior, instalado na metáfise tibial foi utilizado para o ensaio biomecânico, descrito no capítulo I; e o implante localizado abaixo deste, instalado na epífise tibial foi utilizado para o estudo histométrico, descrito no capítulo II. A morfologia das superfícies dos implantes foi analisada por microscopia eletrônica de varredura (MEV), e por espectroscopia de energia dispersiva de raios X (EDS) antes, e após 4 semanas de implantação e remoção por torque reverso. Medidas de rugosidade e secção transversal foram obtidas. Após períodos de 4, 8, e 12 semanas realizou-se o ensaio biomecânico, e após os animais sofreram eutanásia. As peças do implante localizado na epífise tibial foram levadas ao micrótomo para corte sem descalcificação. A análise histométrica foi realizada empregando-se microscopia óptica. Foi mensurada a extensão linear de contato entre osso e implante (ELCOI), e a área óssea (AO). Uma lâmina de cada superfície do período de 4 semanas foi metalizada para realização da análise do mapeamento elementar por MEV-EDS. Resultados: A caracterização topográfica mostrou diferenças entre as superfícies analisadas, e os valores de rugosidade média das SL e SS foram estatisticamente superiores (p<0,05) a SA. Na comparação estatística dos valores obtidos pelo ensaio biomecânico, verificou-se em 4 semanas que os implantes SS e SL apresentaram torque de remoção superior (p<0,05) aos SU e...

Purpose: The aim of this study was to compare the biologic and mechanical behavior of bone tissue around implants with commercially available surfaces, modified by acid etching (SA), and machined surfaces (SU), with the experimental surfaces modified by laser (SL), and modified by laser with silica deposition (SS), using biomechanical, topographic and histometric analyses. Materials and Methods: Thirty rabbits received 120 implants measuring 3,75x10mm in their right and left tibias, being two implants of each type of surface per tibia. The implant located in the uppermost position, inserted in the tibial metaphysis, was used for the biomechanical test, described in Chapter I; and the implant located below this, inserted in the tibial epiphysis, was used for the histometric study, described in Chapter II. The morphology of the implant surfaces was analyzed by scanning electron microscopy (SEM) and by energy dispersive X-ray spectrometry (EDS) before and after 4 weeks of implantation and removal by reverse torque. Mean roughness and cross-sectional measurements were obtained. After periods of 4, 8, and 12 weeks the biomechanical test was performed, and after this the animals were euthanized. The parts of the implant located in the tibial epiphysis were taken for cutting nondecalcified on a microtome. Histometric analysis was performed using an optical microscope. The bone interface contact (BIC), and the bone area (AO) were measured in percentages. A slide of each surface in the period of 4 weeks was metalized in order to analyze the element mapping by means of SEM-EDS. Results: The topographic characterization showed differences between the analyzed surfaces, and the mean roughness values of SL and SS were statistically higher (p<0,05) than those of SA. In the statistical comparison of the values obtained by the biomechanical test, it was verified that at 4 weeks the implants SS and SL presented a higher removal torque (p<0,05) than SU and SA. At 8 weeks the...

Seasonal variations in the histometric characteristics of the reproductive organs of pubertal West African dwarf bucks in their native tropical environment / Variaciones estacionales en las características morfométricas de los órganos reproductivos de la cabra enana púber macho del Oeste Africano en su medio ambiente nativo tropical

As ambient temperature and humidity are high all year round within clearly defined dry and rainy seasons in our humid tropical environment, we evaluated the effects of season on the histometric characteristics of the reproductive organs of pubertal West African dwarf bucks using 8 healthy animals. There were no significant differences (p>0.05) between the rainy and dry seasons in the basement membrane of the testes, seminiferous tubular diameter, and round spermatid nuclear diameter. There were also similarities (p>0.05) between the seasons in epididymal luminal diameters, epididymal epithelial heights as well as in Leydig/sertoli cell ratio and sertoli cell Índex. Quadratic regression analyses showed that all the histometric characteristics of the testes are highly predictable from the live weights of the animals. It is concluded from these results that the WAD goat would not have a restricted breeding season in it native tropical environment. Young sires could therefore be selected early in life for planned improvement programmes in research institutions and breeding centers thus providing farmers with quicker returns for their investments.

Como la temperatura ambiental y la humedad son altas durante todo el año dentro de estaciones secas y lluviosas claramente definidas en nuestro ambiente húmedo tropical, se evaluaron los efectos de las estaciones en la características histométricas de los órganos reproductivos de cabras enanas machos púber del Africa Occidental, usando 8 animales sanos. No hubo diferencias significativas (p> 0,05) entre las estaciones de lluvia y secas, en la membrana basal de los testículos, diámetro de los túbulos seminíferos, y el diámetro de la envoltura nuclear espermática. Sin embargo, hubo similitudes (p> 0,05) entre las diferentes estaciones en el diámetro luminal del epidídimo, altura del epitelio del epidídimo, así como en la proporción de células Leydig/Sertoli e índice de células de Sertoli. El análisis de regresión cuadrática mostró que todas las características histométricas de los testículos son altamente predecibles desde el peso de los animales vivos. Se concluye de estos resultados, que las cabras enanas del Africa Occidental no tendrían una restricción estacional para tener crías en el ambiente tropical nativo. Padres jóvenes por lo tanto, podrían ser seleccionados tempranamente en la vida para programas de mejora planeados en instituciones de investigación y centros criadores los que provean a granjeros de rápidos retornos por sus inversiones.

The correlation of bone probing, radiographic and histometric measurements / 대한치주과학회지

The most accurate method to assess bone level is the histometric measurement. However it causes discomfort in patients and damage to the regenerated tissues. in the present study, we used 4 type regenerative therapies. The present study evaluated the clinical reliability and accuracy of bone probing measurements and radiographic bone level in the assessment of bone level by comparing those results with histometric confirmed bone level. Twentyfour(24) intrabony defects(4x4mm 1-wall intrabony defects) were surgically created in the mandibular second and fourth premolars of 6 beagle dogs. The control group underwent a conventional flap operation. Experimental group 1 was treated with calcium phosphate glass only, and while experimental group 2 was treated with GTR and experimental group 3 was treated with calcium phosphate glass and GTR. The subjects were sacrificed 8 weeks after the operation and a bone probing measurements, radiographic measurement and histometric measurement was performed. The correlation between bone probing measurements(BP) and histometric measurement(HL), and radiographic measurement(RL) and histometric measurement(HL) were analyzed with Spearman's rank correlation analysis and the statistical significance with respect to the type of regenerative therapies was analyzed with the Kruskal Wallis test. The coefficeint of correlation to HL was 0.73 for RL and 0.90 for BP. The type of regenerative therapies had no significant effect on the difference between HL and other measurements. The results of this study suggests that bone probing measurements most closely represents actual bone level. So bone probing measurements may be a good clinical method for assessing the bone level following any type of periodontal regenerative therapies.