Evaluation of Maxillary Sinus Septa Prior to Dental Implant Therapy: A Cone Beam Computed Tomography Study / Evaluación del Septo del Seno Maxilar Antes del Tratamiento con Implantes Dentales: Un Estudio con Tomografía Computarizada de Haz Cónico

SUMMARY: The objective of this study was to investigate the prevalence and location of maxillary sinus septa prior to dental implant therapy in different age groups by cone beam computed tomography (CBCT) and identify the most helpful orthogonal plane for this purpose. CBCT scans of 200 patients were selected. The final sample was divided into four groups according to age: (1) 30-39 y.o.; (2) 40-49 y.o.; (3) 50-59 y.o.; (4) +60 y.o. Three calibrated examiners assessed the presence and location (anterior, middle, posterior) of sinus septa using all orthogonal slices. The prevalence of septa per region and plane was compared by chi-square test. Among 359 maxillary sinuses evaluated, it was observed at least one septum in 163 sinuses (45.4 %). Overall, the anterior region was the most prevalent. However, when the age groups were considered, the anterior region was only the most prevalent in groups 2 and 3. The middle and posterior regions were more prevalent in groups 4 and 1, respectively. In conclusion, the prevalence of maxillary sinus septa in patients who were candidate to dental implant therapy was notably high. It was observed that the anterior region of the sinus was the most prevalent and the axial slice was the most representative.

RESUMEN: El objetivo de este estudio fue investigar la prevalencia y localización del septo del seno maxilar antes del tratamiento con implantes dentales en diferentes grupos etarios, por medio de la Tomografía Computarizada de Haz Cónico (TCHC). Fueron seleccionadas TCHC de 200 pacientes. La muestra final fue dividida en cuatro grupos de acuerdo con la edad: (1) 30-39 años; (2) 40-49 años; (3) 50-59 años y (4) +60 años. Tres examinadores calibrados evaluaron la presencia y localización (anterior, media o posterior) del septo del seno maxilar usando todas las secciones ortogonales. La prevalencia del septo por región y plano fue comparada mediante el test x-cuadrado. Entre los 359 senos maxilares evaluados, fue observado por lo menos un septo en 163 senos (45,4 %). Generalmente la región anterior fue la más prevalente. Sin embargo, cuando fueron considerados los grupos etarios, solamente la región anterior fue la más prevalente en los grupos 2 y 3. Las regiones media y posterior fueron las más prevalente en los grupos 4 y 1, respectivamente. La prevalencia del septo del seno maxilar en pacientes que son candidatos a tratamiento con implantes dentales fue notablemente alta. Se observó que la región anterior fue la más prevalente siendo las secciones axiales las más representativas.

Oral implant osseointegration model in C57Bl/6 mice: microtomographic, histological, histomorphometric and molecular characterization

Abstract Despite the successful clinical application of titanium (Ti) as a biomaterial, the exact cellular and molecular mechanisms responsible for Ti osseointegration remains unclear, especially because of the limited methodological tools available in this field. Objective: In this study, we present a microscopic and molecular characterization of an oral implant osseointegration model using C57Bl/6 mice. Material and Methods: Forty-eight male wild-type mice received a Ti implant on the edentulous alveolar crest and the peri-implant sites were evaluated through microscopic (μCT, histological and birefringence) and molecular (RealTimePCRarray) analysis in different points in time after surgery (3, 7, 14 and 21 days). Results: The early stages of osseointegration were marked by an increased expression of growth factors and MSC markers. Subsequently, a provisional granulation tissue was formed, with high expression of VEGFb and earlier osteogenic markers (BMPs, ALP and Runx2). The immune/inflammatory phase was evidenced by an increased density of inflammatory cells, and high expression of cytokines (TNF, IL6, IL1) chemokines (CXCL3, CCL2, CCL5 and CXC3CL1) and chemokine receptors (CCR2 and CCR5). Also, iNOS expression remained low, while ARG1 was upregulated, indicating predominance of a M2-type response. At later points in time, the bone matrix density and volume were increased, in agreement with a high expression of Col1a1 and Col21a2. The remodelling process was marked by peaks of MMPs, RANKL and OPG expression at 14 days, and an increased density of osteoclasts. At 21 days, intimate Ti/bone contact was observed, with expression of final osteoblast differentiation markers (PHEX, SOST), as well as red spectrum collagen fibers. Conclusions: This study demonstrated a unique molecular view of oral osseointegration kinetics in C57Bl/6 mice, evidencing potential elements responsible for orchestrating cell migration, proliferation, ECM deposition and maturation, angiogenesis, bone formation and remodeling at the bone-implant interface in parallel with a novel microscopic analysis.

Effects of hyperbaric oxygen treatment on implant osseointegration in experimental diabetes mellitus

Abstract Objective To evaluate whether hyperbaric oxygen (HBO) treatment has a favorable effect on implant osseointegration in diabetic rabbits. Material and Methods An experimental diabetes model was induced in 32 New Zealand rabbits through IV injection of alloxan. After the state of diabetes had been confirmed, one dental implant was placed in the metaphysical region of each animal's tibia. After the implants' placements, the animals were divided into two groups. Half of the animals underwent HBO treatment, while the other group did not receive HBO treatment and served as the control group. The animals were euthanized at the 4th and 8th weeks. The osseointegration of the implants were compared by histomorphometry and resonance frequency analysis (RFA). Results The Bone Implant Contact (BIC) values were significantly higher in the HBO group than in the control group at the 4th week. There was no difference in the BIC values between the groups at the 8th week. There was no significant difference in the RFA scores between the groups both at the 4th and 8th weeks after the operation. Conclusion Histomorphometry findings suggest that HBO has positive effect on implant osseointegration in the early healing period in diabetic rabbits. However, implant stability is not affected by HBO treatment.

Functional investigation of bone implant viability using radiotracers in a new model of osteonecrosis

OBJECTIVES: Conventional imaging methods are excellent for the morphological characterization of the consequences of osteonecrosis; however, only specialized techniques have been considered useful for obtaining functional information. To explore the affinity of radiotracers for severely devascularized bone, a new mouse model of isolated femur implanted in a subcutaneous abdominal pocket was devised. To maintain animal mobility and longevity, the femur was harvested from syngeneic donors. Two technetium-99m-labeled tracers targeting angiogenesis and bone matrix were selected. METHODS: Medronic acid and a homodimer peptide conjugated with RGDfK were radiolabeled with technetium-99m, and biodistribution was evaluated in Swiss mice. The grafted and control femurs were evaluated after 15, 30 and 60 days, including computed tomography (CT) and histological analysis. RESULTS: Radiolabeling achieved high (>95%) radiochemical purity. The biodistribution confirmed good blood clearance 1 hour after administration. For 99mTc-hydrazinonicotinic acid (HYNIC)-E-[c(RGDfK)2, remarkable renal excretion was observed compared to 99mTc-methylene diphosphonate (MDP), but the latter, as expected, revealed higher bone uptake. The results obtained in the control femur were equal at all time points. In the implanted femur, 99mTc-HYNIC-E-[c(RGDfK)2 uptake was highest after 15 days, consistent with early angiogenesis. Regarding 99mTc-MDP in the implant, similar uptake was documented at all time points, consistent with sustained bone viability; however, the uptake was lower than that detected in the control femur, as confirmed by histology. CONCLUSIONS: 1) Graft viability was successfully diagnosed using radiotracers in severely ischemic bone at all time points. 2) Analogously, indirect information about angiogenesis could be gathered using 999mTc-HYNIC-E-[c(RGDfK)2. 3) These techniques appear promising and warrant further studies to determine their potential clinical applications.

Avaliação histológica e histomorfométrica da energia superficial e molhabilidade em implantes de titânio grau IV e grau V: estudo experimental em coelhos / Histologic and histomorphometric evaluation of surface energy and wettability in dental implants of titanium grade IV and V: experimental study in rabbits

O presente estudo teve como objetivo avaliar a resposta biológica ao redor de implantes de titânio grau IV (titânio comercialmente puro) e grau V (Ti6Al4V), com diferentes tipos de tratamentos de superfície através da análise do contato ossoimplante (bone implant contact - BIC) e da área de neoformação óssea com e sem fluorocromo (bone area BA e BAfluo) das 3 primeiras roscas em contato ósseo de cada implante. Para isso, utilizou-se um total de 90 implantes Cone Morse de titânio grau IV (Drive 45 implantes) e titânio grau V (Facility 45 implantes), com dimensões de 3.5x8mm e 2.9x7mm, respectivamente. Estes dois tipos de implantes foram avaliados em três tratamentos de superfícies diferentes: a) superfície com jateamento com partículas abrasivas seguido de tratamento ácido - NeoPoros (NP) - em embalagem seca (Grupo Controle); b) superfície jateada seguido de tratamento ácido e energia de superfície, armazenado em líquido (ESm); c) superfície jateada seguido de tratamento ácido com energia de superfície e embalado a seco (ESs); totalizando 6 grupos, distribuídos em 15 coelhos New Zealand, em cada um foram instalados 6 implantes, sendo 3 em cada tíbia. Após 15 dias de osseointegração, os coelhos passaram por eutanásia e as tíbias seccionadas, fixadas e incluídas para a avaliação histológica e histomorfométrica. Mensurações no analisador de imagens ImageJ foram realizadas e a análise dos dados estatísticos, de todos os grupos foram avaliados através da análise de variância a dois critérios e do teste de Tukey para comparações múltiplas grupo a grupo, adotando o nível de significância de 5% (p<0,05). Os resultados mostraram que não houve diferença estatisticamente significante entre os dois tipos de titânio, porém houve diferença estatisticamente significante entre os tipos de superfície em relação ao BIC, BA e BAfluo; também, não houve interação entre titânio e superfície. Na análise do contato osso-implante (BIC) a superfície ESm teve melhor desempenho em relação ao NP, que por sua vez foi semelhante ao ESs. Quanto à área óssea (BA), a superfície NP teve menor desempenho em relação à ESs, este obteve semelhante desempenho a ESm. Quanto a área ósseo neoformada com presença de fluorocromo (BAfluo), NP teve menor desempenho em relação ao ESs, o qual obteve semelhante comportamento a ESm. Com isso, concluiu-se que implantes de titânio de gau IV e grau V obtiveram respostas biológicas equivalentes, enquanto que a energia de superfície com a molhabilidade podem ser consideradas como vantagem, uma vez que otimizam o processo de osseointegração.(AU)

This study aimed to evaluate the biological response around grade IV (commercially pure titanium) and grade V (Ti6Al4V) titanium implants with different types of surface treatments by analyzing bone-implant contact (BIC) and the bone formation area with and without fluorochrome (BA and BAfluo) of the 3 first threads on bone contact of each implant. To this end, this study used 90 Morse Taper grade IV (Drive - 45 implants) and grade V (Facility - 45 implants) titanium implants, measuring 3.5x8mm and 2.9x7mm, respectively. Both types of implants were evaluated in three different surface treatments: a) blasted/acid-etched implant surface - NeoPoros (NP) - dry pack (control group); b) blasted/acid-etched implant surface and surface energy, stored in liquid (ESm); c) blasted/acid-etched implant surface with surface energy and dry packed (ESs); totalizing 6 groups, distributed in 15 New Zealand rabbits. Six implants were placed in each rabbit, 3 in each tibia. After 15 days of osseointegration, the rabbits were euthanized and the tibias sectioned, fixed and embedded for histologic and histomorphometric evaluation. Measurements were carried out using the image analysis program ImageJ and the assessment of statistical data concerning all groups was done through the two-way analysis of variance and the Tukey test for multiple comparisons group to group, adopting the significance level of 5% ( p <0.05). The results showed no statistically significant difference between the types of titanium used. However, there were statistically significant differences between the types of surface in relation to the BIC, BA and BAfluo. In addition, there was no interaction between titanium and the surface. Concerning the analysis of bone-implant contact (BIC), the ESm surface had better performance compared to the NP, which, in turn, was similar to the ESs. As for bone area (BA), the NP surface had lower performance in relation to the ESs surface, as the latter had a similar performance to the ESm surface. Concerning the newly formed bone area with presence of fluorochrome (BAfluo), the NP had lower performance if compared to the ESs, which behaved similarly to that of the ESm surface. Thus, this study concluded that grade IV and grade V titanium implants showed equivalent biological responses, while the surface energy, together with its wettability, can be considered an advantage, enhancing the osseointegration process.(AU)

Total Hip Arthroplasty around the Inception of the Interface Bioactive Bone Cement Technique

BACKGROUND: To augment cement-bone fixation, Dr. Hironobu Oonishi attempted additional physicochemical bonding through interposition of osteoconductive crystal hydroxyapatite (HA) granules at the cement-bone interface in 1982. He first used the interface bioactive bone cement (IBBC) technique in 12 selected patients (12 hips) in 1982 (first stage) and followed them for 2 years. In 1985, the technique was applied in 25 total hip arthroplasty (THA) patients (second stage) and the effects were investigated by comparing the side with the IBBC technique and the other side without the IBBC technique. He has employed this technique in all THA patients since 1987 (third stage). METHODS: In the IBBC technique, HA granules (2 to 3 g) were smeared on the bone surface just before the acetabular and femoral components were cemented. In the first stage, 12 hips were operated using the IBBC technique in 1982. In the second stage, THA was performed without the IBBC technique on one side and with the IBBC technique on the other side within 1 year in 25 patients. In the third stage, THA was performed with the IBBC technique in 285 hips in 1987. RESULTS: In the first stage patients, implant loosening was not detected at 30 years after operation. In the second stage patients, revision was required in 7 hips without the IBBC technique due to cup loosening (5 hips) and stem loosening (2 hips), whereas no hip was revised after THA with the IBBC technique at 26 years after operation. In the third stage patients, the incidence of radiolucent lines and osteolysis was very few at 25 years after operation. CONCLUSIONS: The long-term follow-up of THA performed around the inception of the IBBC technique has revealed low incidences of radiolucent lines, osteolysis, and revision surgery.