RESUMO
PURPOSE: Assess the role of tenting screws in the remodeling processes of autogenous bone blocks used for mandibular lateral augmentation in rabbits. METHODS: Eighteen rabbits, approximately 3.5-4.0 kg of weight and 4-5 months of age, were included in this study. One lateral side of the angle of the mandible was augmented with block autografts. Animals were euthanized after 7, 20 and 60 days of healing, respectively. Biopsies were taken for each period and specimens underwent microtomographic scanning. The total volume (TV, mm3), bone volume (BV: residual graft plus new bone, mm3), periimplant bone volume (PIBV), bone implant contact (BIC) along the screw and linear bone gain at five vertical points symmetrically dispersed from the fixation screw in the midline were measured. ANOVA and the t-test were performed. RESULTS: The total volume (TV) of autografts decreased between 7 and 60 days from 258.13±15.3 mm3 to 107.2 ± 17.5 mm3 (p < 0.05). Contraction rates of 58.5% were observed. BV was 52.8 ± 7.7 mm3, 27.2 ± 11.1 mm3, and 33.1 ± 2.8 mm3 after 7, 20, and 60 days of healing, respectively. PIBV and BIC remained unchanged along time demonstrating no contraction around the screw. Total linear bone gain demonstrated a total of 18% linear contraction after 60 days. Point 1, demonstrated no changes along time representing no resorption along time. Points 2 and 4 demonstrate a minimum linear contraction (10-15%) with borderline significance. Resembling the total results, contraction starts after 20 days. Points 3 and 5 demonstrate a statistically significant contraction (p<0.05) of 35-40% starting at 20 days. CONCLUSION: Tenting screws may reduce bone resorption symmetrically in a model of lateral block augmentation.
Assuntos
Aumento do Rebordo Alveolar , Aumento do Rebordo Alveolar/métodos , Animais , Autoenxertos/cirurgia , Parafusos Ósseos/efeitos adversos , Transplante Ósseo/métodos , Humanos , Mandíbula/cirurgia , CoelhosRESUMO
BACKGROUND: The volumetric and biological behaviors of equine block grafts compared with autogenous block grafts have not yet been assessed. Hence, the aim of the present study was to compare-by means of histomorphometry, immunohistochemistry and microtomography-the graft incorporation and remodeling processes of autogenous and equine xenogenous bone blocks used for mandibular lateral augmentation in rabbits. METHODS: Autogenous bone grafts harvested from the iliac bony crest and equine block grafts were secured to the lateral aspect of the mandible angle of eighteen rabbits. The healing after 7, 20 and 60 days was assessed in six animals each period. RESULTS: After 60 days, new bone was present 24.2 ± 11.2% and 31.6 ± 13.3% in the autograft and xenograft groups, respectively. A better integration to the recipient sites was observed in the autogenous compared with the xenogenous blocks. CONCLUSIONS: Both xenogenous and autogenous bone blocks presented similar percentages of newly formed bone over time. However, bone volume, the quality of the grafted area and graft incorporation to the recipient sites were superior in the autogenous compared with the equine xenogenous graft sites.
RESUMO
BACKGROUND: Due to the lack of data comparing the biological behavior of two formulations, granules and paste, of alloplastic graft from microtomographic and histomorphometric points of view, the aim of the present experiment was to compare the histomorphometric and microtomographic healing of two formulations, i.e., granules (MR sites) or paste (MR-inject sites) of an alloplastic graft composed of a combination of beta-tricalcium phosphate and hydroxyapatite used for maxillary sinus lifting. METHODS: A sinus lifting procedure was carried out bilaterally in 20 rabbits, and the elevated space was filled with either paste or granules of an alloplastic material. A collagen membrane was placed on the antrostomy and the animals were euthanized after 2 or 10 weeks, 10 animals each group. Microtomographic and histological analyses were performed. RESULTS: Higher proportions of new bone formation were found at the MR, compared to the MR-inject sites both after 2 weeks (2.65 ± 2.89% vs. 0.08 ± 0.12%; p < 0.01) and 10 weeks of healing (34.20 ± 13.86 vs. 23.28 ± 10.35%; p = 0.022). CONCLUSIONS: It was concluded that new bone formation was faster in the MR sites, compared to the MR-inject. However, a longer time of healing should be allowed to make final conclusions about the efficiency in bone formation of the paste formulation of the biomaterial used in the present study.
RESUMO
BACKGROUND: Due to the lack of data on bone-to-graft contact (BGC) over time in the various regions within the subantral space of the augmented sinus floor, the present study aimed to evaluate the osteoconductivity of deproteinized bovine bone mineral (DBBM) with granules of different sizes applied in maxillary sinus floor elevation. METHODS: A maxillary sinus augmentation was performed bilaterally in 18 rabbits using DBBM with particle dimensions of either 0.125-1.0 mm or 1-2 mm. The antrostomy was covered using a collagen barrier. The animals were euthanized in groups of six after 2, 4, and 8 weeks of healing. MicroCT and histological analyses were performed. RESULTS: After 2 weeks of healing, BGC was 10.9% and 11.9% for the small and large granule sites, respectively. After 8 weeks of healing, the BGC increased to 65% and 62% at the small and large granule sites, respectively. The highest values were located close to the bony walls and the bony window. New bone content developed between 2 and 8 weeks from 7.0% to 27.6% and from 6.1% to 27.6% at the small and large granule sites, respectively. CONCLUSIONS: Similar outcomes in osteoconductivity and bone formation were found at both small and large DBBM granule sites.
RESUMO
Stafne's bone cavity (SBC) is an asymptomatic lingual bone cavity situated near the angle of the mandible. The anterior variant of SBC, which shows a radiolucent unilateral ovoid lingual bone concavity in the canine-premolar mandibular region, is uncommon. A 73-year-old man was referred for assessment of loss of mandibular bone. Panoramic radiographs and computerized tomography scans showed a well-defined lingual bony defect in the anterior mandible. Analysis of imaginological documentation, made 14 years ago, revealed a progressive increase in mesiodistal diameter and intraosseous bony defect. The soft tissue obtained within the bony defect, microscopically revealed fibrous stroma containing blood vessels of varied caliber. The current anterior lingual mandibular bone defect case is probably caused by the salivary gland entrapped or pressure resorption, which can explain the SBC pathogenesis (AU)
A cavidade óssea de Stafne (COS) é uma cavidade assintomática, localizada próximo ao ângulo da mandíbula, por lingual. A variante anterior da COS, a qual apresenta uma concavidade óssea lingual radiolúcida, ovoide e unilateral na região do caninopré-molar mandibular, é incomum. Um homem de 73 anos foi encaminhado para avaliação da perda óssea mandibular. A radiografia panorâmica e a tomografia computadorizada mostraram um defeito ósseo lingual bem definido na região anterior da mandibula. A análise da documentação imaginológica, realizada há 14 anos, revelou um aumento progressivo do diâmetro mesiodistal e defeito ósseo intraósseo. A biópsia do tecido mole obtido do defeito ósseo revelou microscópicamente estroma fibroso contendo vasos sanguíneos de calibre variado. O presente caso de defeito ósseo mandibular na região lingual anterior é provavelmente causado por glândula salivar aprisionada ou reabsorção por pressão, o que pode explicar a patogênese da COS. (AU)
Assuntos
Humanos , Masculino , Idoso , Perda do Osso Alveolar , Diagnóstico , Tomografia Computadorizada de Feixe Cônico , Mandíbula , BocaRESUMO
Fresh frozen bone allografts (FFB) have become an alternative for bone augmentation in the past decades, especially because of the absence of recent reports of disease transmission or immunologic reactions when it is used. The aim of this prospective controlled study is to evaluate volumetric changes of newly created bone following reconstruction of the atrophic posterior mandible. Twenty consecutive patients presenting for reconstruction of posterior mandibular alveolar bone ridge width ≤6.0 mm and/or height ≤6.0 who met all inclusion and exclusion criteria were included. FFB blocks were used. The main outcome variable investigated was bone volume dynamics. Vertical, horizontal, and 3-dimensional bone gain data were measured from computerized tomography scans. The main predictor variable was time evaluated at 3 points: immediately after surgery (T1), at implant placement (T2), and 1 year after functional loading (T3). Secondary outcome parameters evaluated were implant survival, histologic findings, and microtomographic morphometry. The study included 28 hemi-mandibles, 50 FFB bone blocks, and 15 female and 5 male patients (mean age, 51.8 years). Block and implant survival rates were 100% and 96%, respectively, after 31.75 months of follow-up. Vertical and horizontal bone gain at T2 was 5.15 and 6.42 mm, respectively. Volumetric resorption was 31% at T2, followed by an additional 10% reduction at T3. Histologic evaluation showed newly formed vital bone in intimate contact with the remaining FFB. Microtomography revealed 31.8% newly formed bone, 14.5% remaining grafted bone, and 53.7% connective tissue and bone marrow. Thus, FFB blocks may lead to new bone formation and consolidation, with satisfactory volumetric bone maintenance, allowing implant-supported rehabilitation with high success rates.
Assuntos
Aumento do Rebordo Alveolar , Implantação Dentária Endóssea , Implantes Dentários , Transplante Ósseo , Feminino , Seguimentos , Humanos , Masculino , Mandíbula , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do TratamentoRESUMO
We evaluated histologically and tomographically the effects of fresh frozen bone allograft (FFB) or bovine bone mineral (BBM) in maxillary sinus floor augmentations. In total, 30 maxillary sinuses from 30 patients (mean age = 51.17 ± 10.86 years) underwent sinus augmentation. Patients were divided in two test groups (15 sinuses each). The first group was grafted with allograft bone, and the second group received bovine bone mineral. After 6 months, bone samples from each group were collected for histological examination. Implant survival rates were 97.78% (FFB group) and 100% (BBM group) 6 months after functional loading. Median volumetric reductions of 31.2% (11.33-40.56) and 12.22% (9.91-20.59) were observed in the FFB and BBM groups, respectively. Comparisons between the groups for differences in initial and final volumes of bone (p = 0.015) and the rate of resorption (p = 0.009) showed statistically significant differences. The FFB group showed osteoblastic cells in close contact with osteoid matrix, connected through bridges between allograft bone particles and new bone formation. The BBM group showed BBM particles in close contact with new bone, with visible osteoid matrix bridges and osteoblastic cells surrounding it. None showed signs of acute or chronic inflammatory infiltrate. Despite better results with BBM, both FFB and BBM in maxillary sinus augmentation resulted in high percentages of new bone formation, and allowed implant placement with a low rate of failure of osseointegration at a 6-month follow-up.
Assuntos
Seio Maxilar/cirurgia , Levantamento do Assoalho do Seio Maxilar/métodos , Adulto , Idoso , Aloenxertos , Animais , Transplante Ósseo/métodos , Bovinos , Feminino , Sobrevivência de Enxerto , Humanos , Masculino , Seio Maxilar/diagnóstico por imagem , Seio Maxilar/patologia , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios XRESUMO
Patients with bisphosphonate-related osteonecrosis of the jaws (BRONJ) who received intravenous or oral bisphosphonates (BP) were selected for determination of their bone microarchitecture as a risk predictor of BRONJ development. The diagnosis of BRONJ was made based on clinical and radiographic findings. The control group consisted of healthy patients. All patients underwent quantitative and qualitative ultrasound measurements of bone at the hand phalanges carried out using the DBM Sonic BP. Ultrasound bone profile index (UBPI), amplitude-dependent speed of sound (AD-SoS), bone biophysics profile (BBP), and bone transmission time (BTT) were measured. The BRONJ group consisted of 17 patients (62 ± 4.24; range: 45-82); 10 (58.8%) were male and seven (41.1%) were female, of whom 11 (64.7%) suffered from multiple myeloma, three (17.6%) from osteoporosis, one (5.8%) from prostate cancer, one (5.8%) from kidney cancer, and one (5.8%) from leukemia. Fourteen (82.3%) of them received intravenous BP whereas three (17.6%) received oral BP. Nine (9/17; 52.9%) patients developed bone exposure: two in the maxilla and seven in the mandible. Regarding quantitative parameters, Ad-SoS was low in the BRONJ group, but not significant. The UBPI score was significantly reduced in BRONJ patients with exposed bone when compared to controls (0.47 ± 0.12 vs. 0.70 ± 0.15; p = 0.004). The present study demonstrated that quantitative ultrasound was able to show bone microarchitecture alterations in BRONJ patients, and suggests that these analyses may be an important tool for early detection of bone degeneration associated with BRONJ.
Assuntos
Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/diagnóstico por imagem , Falanges dos Dedos da Mão/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/patologia , Osteonecrose da Arcada Osseodentária Associada a Difosfonatos/fisiopatologia , Densidade Óssea , Remodelação Óssea/fisiologia , Estudos de Casos e Controles , Estudos Transversais , Feminino , Falanges dos Dedos da Mão/patologia , Falanges dos Dedos da Mão/fisiopatologia , Mãos/diagnóstico por imagem , Humanos , Arcada Osseodentária/diagnóstico por imagem , Arcada Osseodentária/patologia , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/patologia , Osteoporose/induzido quimicamente , Reprodutibilidade dos Testes , Fatores de Risco , Fatores de Tempo , UltrassonografiaRESUMO
We evaluated histologically, histomorphometrically, and tomographically the effects of the association of fresh-frozen bone allograft (FFB) with bovine bone mineral (BBM) in maxillary sinus floor augmentation. In total, 34 maxillary sinuses from 29 patients, with a mean age of 51.32 (±6.44) years, underwent sinus augmentation. Patients were divided into control and test groups (17 sinuses each). The controls were grafted with allograft bone, and the test group received a combination of FFB and BBM at a 2:1 ratio. After 6 months, bone samples were collected for histological and histomorphometric examinations. The implant survival rates were 93.02% (control group) and 100% (test group) at 6 months after functional loading. Median volumetric reductions of 28.32% (17.05-44.05) and 12.62% (5.65-16.87) were observed for the control and test groups, respectively. Statistically significant histomorphometric differences were found between the control and test groups regarding newly formed bone 12.54% (10.50-13.33) vs. 24.42% (17.62-35.92), p < 0.001, total bone 48.34% (39.03-54.42) vs. 61.32% (50.61-64.96), p = 0.007, and connective tissue 51.66% (45.57-60.97) vs. 39.30% (35.03-49.37), p = 0.007. The addition of BBM to allograft bone in maxillary sinus augmentation resulted in higher percentages of new bone formation and total bone, and permitted implant placement with a low rate of osseointegration failure at the 6-month follow-up.