PLA/PGA copolymer as a bone substitute in maxillary sinus augmentation: histological, histometric and immunohistochemistry study in rabbits

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Calvarial Autogenous Bone Graft for Maxillary Ridge and Sinus Reconstruction for Rehabilitation With Dental Implants

Autogenous bone grafting is the gold-standard technique for bone augmentation procedures prior to implant placement. If the amount of available intraoral donor bone is insufficient, it is necessary to harvest bone graft from extraoral sites, such as calvaria. Although this technique is well established, only a few case reports show the histological analysis of the grafted bone at the moment of implant placement. This article reports the case of a 48-year-old female patient with a critical atrophic maxillary ridge reconstructed using autogenous calvarial bone graft prior to implant placement, with clinical and histological evaluation. Bone was collected under general anesthesia from the parietal bone. The outer cortical originated the bone blocks, and the medullar bone layer between was collected to be used in the sinus augmentation procedure, together with 5 of the bone blocks triturated. Six months after bone augmentation, 8 implants were placed in the grafted area and 2 biopsies were retrieved (anterior and the posterior regions), allowing the visualization of the bone-remodeling process in the grafted areas. The patient had a stable recovery. Our results showed that although necrotic bone could still be seen in the outer layer of the grafted area, the interface between this necrotic bone and the already remodeled bone was consistent with biocompatibility. Two-year radiographic evaluation showed success of the grafts and the implants in supporting an esthetic and functionally stable prosthesis. Summarizing, calvarial bone grafts are a viable alternative for the attainment of adequate bone volume prior to implant placement.

A famacocinética e os efeitos sedativos e comportamentais dos cloridratos de xilazina e de detomidina, administrados por diferentes vias, em asininos Nordestinos (Equus sinus)

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

Aplicação de engenharia tecidual na elevação de seio maxilar: uma revisão sistemática da literatura

The purpose of this literature review is to present the state-of-the-art on the application of tissue engineering techniques in sinus lifts procedures, reporting the influence of these techniques in increasing bone height and volume in the maxillary sinus, and the osseointegration of the implants installed in the grafted areas. PubMed and Scopus databases were searched using the keywords “scaffold” OR “engineered tissue” AND “sinus augmention” OR “sinus floor elevation”. In the initial search 463 articles were selected, of which 19 were selected abstracts reading, with nine papers selected by the end, for evaluation of the application of tissue engineering techniques in sinus lift procedures. Despite the positive results of tissue engineering procedures in sinus floor elevation reported in the selected articles, further studies are still needed, for a better standardization of experimental models and materials used, leading to definitive conclusions about the effects of the application of tissue engineering procedures on bone formation in maxillary sinus lifting procedures.

Alveolar ridge and maxillary sinus augmentation using rhBMP-2: a systematic review

Purpose: The aim of this systematic review was to evaluate clinical and safety data for recombinant human bone morpho-genetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier when used for alveolar ridge/maxillary sinusaugmentation in humans.Materials and Methods: Clinical studies/case ser ies published 1980 through June 2012 using rhBMP-2/ACS were searched.Studies meeting the following criteria were considered eligible for inclusion: >10 subjects at baseline and maxillary sinus oralveolar ridge augmentation not concomitant with implant placement.Results: Seven of 69 publications were eligible for review. rhBMP-2/ACS yielded clinically meaningful bone formationfor maxillary sinus augmentation that would allow placement of regular dental implants without consistent differencesbetween rhBMP-2 concentrations. Never theless, the statistical analysis showed that sinus augmentation following autog-enous bone graft was significantly greater (mean bone height: 1.6 mm, 95% CI: 0.5–2.7 mm) than for rhBMP-2/ACS(rhBMP-2 at 1.5 mg/mL). In extraction sockets, rhBMP-2/ACS maintained alveolar ridge height while enhancing alve olarridge width. Safety reports did not represent concerns for the proposed indications.Conclusions: rhBMP-2/ACS appears a promising alternative to autogenous bone grafts for alveolar ridge/maxillary sinusaugmentation; dose and carrier optimization may expand its efficacy, use, and clinical application.

Frontal sinus obliteration with iliac crest bone grafts: review of 8 cases

This study evaluated postoperative results of 8 cases of frontal sinus fractures treated by frontal sinus obliteration with autogenous bone from the anterior iliac crest. Patients and methods: The medical charts of patients sequentially treated for frontal sinus fractures by obliteration with autogenous cancellous iliac crest bone in the Oral and Maxillofacial Surgery Division of this institution were reviewed. From those, eight had complete records and adequately described long-term follow-up. All were operated by the same surgical team. Those patients were recalled and independently evaluated by 2 examiners. Radiographs and/or CT scans were available for this evaluation. Associated fractures and complications were noted. The average postoperative follow-up was 7 years, ranging from 3 to 16 years. The main complication was infection. Four patients (50%) had uneventful long-term follow-ups and four (50%) experienced complications requiring reoperation. Based on the studied sample studied the authors conclude that the obliteration with autogenous bone presented a high percentage of complications in this series.

Frontal sinus obliteration with iliac crest bone grafts

This study evaluated postoperative results of 8 cases of frontal sinus fractures treated by frontal sinus obliteration with autogenous bone from the anterior iliac crest.

Maxillary sinus lift without grafting, and simultaneous implant placement: a prospective clinical study with a 51-month follow-up

A prospective clinical study of maxillary sinus lift procedures in the posterior region of the maxilla, using only blood clot as filling material, was conducted. Seventeen patients underwent a maxillary sinus lift procedure; 20 maxillary sinus regions were operated on and a total of 25 implants were placed. The sinus mucosa was lifted together with the anterior wall of the osteotomized maxilla and supported by the implants placed. Computed tomography (CT) scans were obtained immediately postoperative (T-initial) and at 3 (T-1) and 51(T-2) months postoperative for the measurement of linear bone height and bone density (by grey tones). Only one implant was lost in the first stage (96% success). After dental prosthesis placement and during up to 51 months of follow-up, no implant was lost (100% success, second stage). The difference in mean bone height between T-initial (5.94 mm) and T-1 (13.14 mm), and between T-initial and T-2 (11.57 mm), was statistically significant (both P < 0.001); comparison between T-1 and T-2 also presented a statistical difference (P < 0.001). Bone density had increased at the end of the period analyzed, but this was not statistically significant (P > 0.05). Thus, the maxillary sinus lift technique with immediate implant placement, filling with blood clot only, may be performed with a high success rate.

Use of autogenous bone and beta-tricalcium phosphate in maxillary sinus lifting: a prospective, randomized, volumetric computed tomography study

The correction of bone defects can be performed using autogenous or alloplastic materials, such as beta-tricalcium phosphate (β-TCP). This study compared the changes in bone volume (CBV) after maxillary sinus lifting using autogenous bone (n=12), autogenous bone associated with β-TCP 1:1 (ChronOS; DePuy Synthes, Paoli, CA, USA) (n=9), and β-TCP alone (n=11) as grafting material, by means of cone beam computed tomography (CBCT). CBV was evaluated by comparing CBCT scans obtained in the immediate postoperative period (5-7 days) and at 6 months postoperative in each group using OsiriX software (OsiriX Foundation, Geneva, Switzerland). The results showed an average resorption of 45.7±18.6% for the autogenous bone group, 43.8±18.4% for the autogenous bone+β-TCP group, and 38.3±16.6% for the β-TCP group. All bone substitute materials tested in this study presented satisfactory results for maxillary sinus lifting procedures regarding the maintenance of graft volume during the healing phase before the insertion of implants, as assessed by means of CBCT.

Frontal sinus recognition for human identification

Many methods based on biometrics such as fingerprint, face, iris, and retina have been proposed for person identification. However, for deceased individuals, such biometric measurements are not available. In such cases, parts of the human skeleton can be used for identification, such as dental records, thorax, vertebrae, shoulder, and frontal sinus. It has been established in prior investigations that the radiographic pattern of frontal sinus is highly variable and unique for every individual. This has stimulated the proposition of measurements of the frontal sinus pattern, obtained from x-ray films, for skeletal identification. This paper presents a frontal sinus recognition method for human identification based on Image Foresting Transform and shape context. Experimental results (ERR = 5,82%) have shown the effectiveness of the proposed method.

The Fresh Frozen Bone Allograft (FFBA) to reconstruc the atrophic maxilla: evaluation of the clinical and histological viability at six and nine months in the maxillary sinus

This work aimed to analyze clinically and histologically the allogen bone graft behavior at 6 and 9 months. A leukoderm, female, 55 years old patient sought dental care for oral rehabilitation with dental implants and implant supported fixed prosthesis in the maxilla. Bilateral sinus lifting procedure were performed in a same patient, the analysis were made after 6 and 9 months, respectively. At 6 months, there was lack of a better bone remodeling in the region, associated to the presence of fibrous connective tissue within the collected tissue, showing us that this is not the best stage of tissue maturation to place dental implants. The 9 months period showed an improvement, with a more organized bone tissue surrounding particles of homogenous bone, what possibly had increased implant stability at the time of surgery. There is no doubt about the increase of clinical applications of FFBA, but there are no studies available regarding the standardization of time to load implants inserted in allografts. So papers with long-term monitoring are necessary to eliminate questions that still remain to be answered.

Reconstruction of the anterior wall of the frontal sinus using bovine bone matrix: histological study with monkeys

The purpose of this study was to evaluate the repair process in the reconstruction of the anterior wall of the frontal sinus of monkeys with bovine bone matrix. Four adult Cebus apella monkeys underwent an ostectomy of the anterior wall of the frontal sinus. The frontal sinus mucosa and the nasofrontal duct were not manipulated. Reconstruction occurred with implants of bovine bone matrix laminae measuring 2.0 x 2.5 cm and 0.4 mm thick, stabilized under pressure in the lateral wall of the frontal sinus. The monkeys were sacrificed over a period of 150 days and routine laboratory procedures were followed for hematoxylin-eosin staining and histologic evaluation of the specimens. Neoformed bone tissue was observed in contact with the frontal sinus mucosa and the bovine bone matrix. The frontal sinus mucosa remained whole without fibrous tissue or cystic formations. There was no occurrence of cellularization as well as revascularization of the bovine bone matrix, though it has permitted bone conduction on this surface. It was possible to conclude that the demineralized bovine bone matrix was biotolerable, being incorporated into the bone without the presence of inflammatory cells with characteristics of inertness and antigenicity and behaved as an osteoconductive material.