Dimensional changes of hard and soft tissues in post-extraction sites: evaluation of two biomaterials / Cambios dimensionales de los tejidos duros y blandos en sitios post-exodoncia: evaluación de dos biomateriales

ABSTRACT Introduction: the techniques for alveolar ridge preservation with different biomaterials show better healing processes and modify the patterns of alveolar bone resorption. The goal of this study was to evaluate the clinical, radiographic, and histological changes of tissues in post-extraction sites after 90 and 180 days by using two biomaterials for alveolar ridge preservation. Materials: descriptive study involving the extraction of twenty-seven uni- and biradicular teeth comparing two biomaterials randomly distributed. Group A received resorbable synthetic hydroxyapatite (OsseoU) and Group B received mineralized freeze-dried allogeneic bone (Tissue Bank®). Quantitative and qualitative measurements were made 180 days post-extraction. The statistical analysis was conducted with the Shapiro-Wilks, Levine, and Student t tests. Results: comparing the two biomaterials on day 180 yielded no statistically significant differences in terms of the "height" variable. The "width" variable yields a p = 0.010 value, suggesting statistically significant differences, since Group A is 0.789 ± 0.276 times better (3.72 ± 0.76) than group B (2.93 ± 0.55). The radiographic evaluation did not yield differences between both groups (p = 0.711). Conclusion: this study shows the dimensional changes of post-extraction sites in both groups, with a clinical difference in ridge width, and no radiographic or histological differences, neither statistically significant changes in terms of alveolar ridge height. Resorbable synthetic hydroxyapatite (OsseoU) is then a biomaterial as effective as mineralized freeze-dried allogeneic bone (Tissue Bank®).

RESUMEN. Introducción: las técnicas de preservación del reborde alveolar con diferentes biomateriales demuestran un mejor proceso de cicatrización que si no se lleva a cabo ningún procedimiento y modifican los patrones de reabsorción del hueso alveolar. El objetivo del presente estudio consistió en evaluar los cambios clínicos, radiográficos e histológicos de los tejidos en sitios post-exodoncia a los 90 y 180 días, utilizando dos biomateriales para la preservación del reborde. Materiales: estudio descriptivo en el que se hacen las exodoncias de veintisiete dientes uni- y birradiculares y se comparan dos biomateriales diferentes repartidos aleatoriamente. El grupo A recibió hidroxiapatita sintética reabsorbible (OsseoU) y el grupo B recibió hueso alogénico mineralizado, secado por congelación (Tissue Bank®). Se hicieron mediciones cuantitativas y cualitativas a los 180 días. El análisis estadístico se realizó con pruebas de Shapiro-Wilks, Levine y t-Student. Resultados: al comparar los dos biomateriales a los 180 días, se observa que en la variable "altura" no existen diferencias estadísticamente significativas. En la variable "amplitud" se establece un valor p = 0,010, lo cual indica que hay diferencias estadísticamente significativas, siendo 0,789 ± 0,276 mejor el grupo A (3,72 ± 0,76) comparado con el grupo B (2,93 ± 0,55). En la evaluación radiográfica no se reportan diferencias entre los dos grupos (p = 0,711). Conclusión: este estudio demuestra cambios dimensionales de los sitios post-exodoncia en ambos grupos, con diferencia clínica en la amplitud de reborde, y sin diferencias radiográficas ni histológicas, ni cambios estadísticamente significativos en cuanto a la altura del reborde. La hidroxiapatita sintética reabsorbible (OsseoU) es entonces un biomaterial igual de efectivo que el hueso alogénico mineralizado, secado por congelación (Tissue Bank®). Palabras claves: técnicas de preservación de reborde, hidroxiapatita sintética, hueso alogénico mineralizado, secado por congelación.

Comparative evaluation of bovine derived hydroxyapatite and synthetic hydroxyapatite graft in bone regeneration of human maxillary cystic defects: A clinico-radiological study.

Introduction: Bone grafts are frequently used in the treatment of bone defects. Bone harvesting can cause postoperative complications and sometimes does not provide a sufficient quantity of bone. Therefore, synthetic biomaterials have been investigated as an alternative to autogenous bone grafts. Aim and Objectives: The aim of this study was to evaluate and compare bovine derived hydroxyapatite (BHA) and synthetic hydroxyapatite (SHA) graft material as bone graft substitute in maxillary cystic bony defects. Patients were analyzed by computerized densitometric study and digital radiography. Materials and Methods: In this study, 12 patients in each group were included randomly after clinical and radiological evaluation. The integration of hydroxyapatite was assessed with mean bone density, surgical site margin, and radiological bone formation characteristics, of the successful graft cases using computer densitometry and radio-visiograph. Statistical analysis was carried out using Mann-Whitney U-test, Wilcoxon matched pairs test and paired t-test. Results: By the end of 24 th week, the grafted defects radiologically and statistically showed similar volumes of bone formation. However, the significant changes observed in the formation of bone and merging of material and surgical site margin at 1 st week to 1 st month. The results were significant and correlating with all the parameters showing the necessity of the grafting for early bone formation. However, the bone formation pattern is different in both BHA and SHA group at 3 rd month interval with significant P value. Conclusion: Both BHA and SHA graft materials are biocompatible for filling bone defects, showing less resorption and enhanced bone formation with similar efficacy. Our study showed maximum bone healing within 12 weeks of grafting of defects. The BHA is economical; however, price difference between the two is very nominal.

Análise histomorfométrica de levantamento de seio maxilar utilizando um novo biomaterial sintético: relato de caso / Histomorphometric analysis of anew synthetic biomaterial for maxillary sinus lifting procedures: case report

O objetivo deste trabalho foi realizar o relato de um caso clínico do tratamento da região posterior da maxila com uma análise clínica e histomorfométrica da neoformação óssea de enxerto em seio maxilar utilizando-se uma nova hidroxiapatita (HA) sintética. Uma paciente de 59 anos usando prótese metalocerâmica fixa extensa e com número reduzido de dentes pilares foi submetida ao levantamento do seio maxilar e colocação de HA. Nove meses depois, a análise histomorfométrica da área regenerada demonstrou a presença de 24,89% de tecido ósseo neoformado, 23,37% de tecido conjuntivo fibroso, 45,67% de biomaterial remanescente e 6,05% de outros tecidos (espaço medulares, vasos sanguíneos e tecido adiposo), demonstrando a interação do novo osso regenerado com o biomaterial. Os torques de inserção nos implantes das regiões 15 e 16 foram de 60 Ncm e 30 Ncm, respectivamente. Não foram relatadas complicações no período pós-operatório. Embora as próteses definitivas ainda não tenham sido instaladas, os resultados encontrados pela histomorfometria neste curto prazo de tempo são compatíveis com os existentes na literatura científica.

The aim of this study was to analyze clinical and histomorphometric bone formation in maxillary sinus graft using a new synthetic hydroxyapatite (HA) material. A 59 years-old female patient presenting large metalloceramic bridgework and few abutment teeth was scheduled for maxillary sinus lifting and HA harvesting. Nine months later, histomorphometric analysis of the regenerated area demonstrated the presence of new bone formation (24.89%), fibrous connective tissue (23.37%), biomaterial remnants (45.67%), and other components (6.05% for bone marrow space, blood vessels, and adipose tissue). Final insertion torques at the regions of teeth 15 and 16 were 60Ncm and 30Ncm, respectively. Although the definitive prostheses have not been delivered yet, the short-term results corroborate the scientific literature on the subject.

Hidroxiapatita sintética como substituto ósseo em defeito experimental provocado no terço proximal da tíbia em cão: aspectos à microscopia eletrônica de transmissão

With the objective of studying the synthetic hydroxyapatite (HAP-91) as a bone substitute, eight healthy mongrel adult dogs were used. Following the habitual anesthetic and surgical protocol, a bone defect was provoked in the proximal diafisis of the left and right tibias, being implanted the graft of HAP-91 just in the right tibia. The animals, two at each time, were sacrificed at the 8th, 30th, 60th and 120th days after the surgery, when lesion samples were obtained for histopathology, submitted to the double coloration in 1% uranil acetate solution and in lead citrate solution. These sections were examined and photographed in an electronic transmission microscope. The bone tissue components were identified both in the control and treated tibia. The absorption of HAP-91 was characterized by the presence of multinuclear cells in the interface between the hydroxyapatite and the bone, morphologically considered as osteoclasts. In addition, the concomitant presence of HAP-91, with the adjacent formation of new bone was found, which suggests that the osteointegration of HAP-91 is similar to the bone reabsorption apposition normal process.

Com o objetivo de estudar a hidroxiapatita sintética (HAP-91) como substituto ósseo, foram utilizados oito cães adultos, sem raça definida, clinicamente sadios. Após protocolo anestésico e cirúrgico habituais, foi provocado um defeito ósseo na diáfise proximal das tíbias esquerda e direita, sendo implantada a HAP-91 apenas na tíbia direita. Os animais, dois de cada vez, foram sacrificados aos 8, 30, 60 e 120 dias após a cirurgia, quando foram obtidas amostras do local da lesão, que foram fixadas, lavadas, polimerizadas, cortadas e submetidas a dupla coloração em solução aquosa de acetato de uranila a 1% e em solução de citrato de chumbo. Essas secções foram avaliadas e fotografadas ao microscópio eletrônico de transmissão. Os componentes tissulares na tíbia tratada e na controle foram similares. A absorção da HAP-91 caracterizou-se pela presença de células multinucleadas na interface entre HAP-91 e osso, morfologicamente consideradas como osteoclastos. Ainda, encontraram-se grânulos de HAP-91 no interior de células morfologicamente caracterizadas como macrófagos. A absorção celular de grânulos de HAP-91, concomitante com a formação adjacente de osso novo, sugere que a osteointegração da HAP-91 seja análoga ao processo normal de reabsorção-aposição óssea.