Osteoconductive Properties of beta-Tricalcium Phosphate Matrix, Polylactic and Polyglycolic Acid Gel, and Calcium Phosphate Cement in Bone Defects

Extensive bone defects in maxillofacial region can be corrected with autogenous grafts; otherwise, the disadvantages of the therapeutics modality take the research for new bone substitutes. The aim of the study was to evaluate and compare the osteoconductive properties of 3 commercial available biomaterials. A total of 30 calvarial defects (5-mm diameter) were randomly divided into 5 treatment groups, with a total of 6 defects per treatment group (n = 6). The treatment groups were as follows: 500 to 1000 Km beta-tricalcium phosphate (beta-TCP), polylactic and polyglycolic acid (PL/PG) gel, calcium phosphate cement, untreated control, and autograft control. The evaluations were based on histomorphometric analysis at 60 postoperative days. The results have shown that beta-TCP and autograft control supported bone formation at 60 postoperative days. beta-Tricalcium phosphate showed the highest amount of mineralized area per total area and statistically significant compared with PL/PG, calcium phosphate cement, and untreated control groups. The PL/PG gel does not have osteoconductive properties and performed similar to empty control. Calcium phosphate cement showed higher number of multinucleated giant cells around the sites of the biomaterial and showed newly formed bone only at the edges of the biomaterial, without bone formation within the biomaterial. The findings presented herein indicate that bone formation reached a maximum level when rat calvarial defects were filled with beta-TCP at 60 postoperative days. Further studies should be conducted with beta-TCP to understand the potential of this biomaterial in bone regeneration.

A modified approach for vestibuloplasty in severely resorbed mandible using an implant-retained postoperative stent: a case report

Background. Severely resorbed mandibles often present a short band of keratinized tissue associated with a shallow vestibule. As a result, prominent muscle insertions are present, especially in the mental region of the mandible. This case report describes the deepening of the vestibular sulcus in an atrophic mandible by combining free gingival grafts harvested from the palate and a postoperative acrylic resin stent screwed on osseointegrated implants placed at the anterior region of the mandible.Study design. During the second-stage surgery, a split-thickness labial flap was reflected and apically sutured onto the periosteum. Two free gingival grafts were obtained and then sutured at this recipient site. A previously custom-made acrylic stent was then screwed onto the most distally positioned implants. To document the procedure's stability over time, a metal ball was placed in the most apical part of the vestibule and standardized cephalometric radiographs were taken before and 6 months after the procedure. Linear measurements of vestibular depths over the observation time were realized using specific software for radiographic analysis.Results. The proposed technique augmented the band of attached masticatory mucosa, deepened the vestibule and prevented the muscle reinsertion. The difference between the 2 measurements of vestibular depths was 9.39 mm (initial 20.88 mm, final 11.49 mm) after a 6-month postoperative period.Conclusion. The technique, in combination with palatal mucosal graft and use of a postoperative stent, decreased the pull of mentalis muscle and provided a peri-implantally stable soft tissue around implants. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008; 106: e7-e14)

The use of transitional implants to support provisional prostheses during the healing phase: a literature review

Objective: Transitional implants are indicated for cases in which immediate loading is counter-indicated because a healing period is necessary for osseointegration of the definitive implants. These provisional implants were developed to support an implant-supported fixed prosthesis or overdenture to provide retention, stability, and support. The aim of this article was to conduct a literature review on transitional implants to highlight the characteristics of the transitional implants and their advantages, indications, and contraindications, including the level of osseointegration of such implants according to the functional period. Method and Materials: The present literature review was based on the OldMedline and Medline databases from 1999 to 2010 using the key words "transitional implants" and "temporary implants." Fourteen articles were found: 11 clinical studies or techniques and three histologic and histomorphometric studies. Results: The transitional immediate prostheses were worn by completely and partially edentulous patients. Advantages of transitional implants include complete denture retention, stability, and support; maintenance of chewing, phonetics, and patient comfort; protection of bone grafts; vertical stop during healing period; easy and fast surgical and prosthetic procedures; lower cost in comparison to the definitive implant; and reestablishment of esthetics. The success of transitional implants as conservative treatment for conventional immediate loading is a reality if correctly indicated. Conclusion: Transitional implants are a provisional treatment alternative for completely and partially edentulous patients. However, additional studies are required to evaluate the level of remodeling and repair of the transitional implants under loading. (Quintessence Int 2011; 42: 19-24)

Surgical and Prosthetic Rehabilitation of Patients With Hemimandibular Defect

Purpose: This work intended to investigate, by means of a literature revision, the techniques and materials used for the rehabilitation of hemimandibular defect patients, prosthetic and occlusal aspects of these patients, and chewing and swallowing.Materials and Methods: For the confection of this revision, we consulted the database indexers Google Scholar, PubMed, and SciELO and found studies published between the periods 1972 and 2008. The terms used for the search had been "to hemimandibular defects," "to temporomandibular joint protheses," and "vascularized cap grafts," which had been searched separately and combined.Conclusions: Diverse techniques and materials used for the reconstruction of hemimandibular defects exist; however, great bone resorption is still observed, which will compromise the prosthetic rehabilitation of these patients. More prospective works and stories of clinical cases duly registered will be able to elucidate in a clearer form the anatomic and functional devolutions of the verbal socket of hemimandibular defect patients.

Maxillo-mandibular counter-clockwise rotation and mandibular advancement with TMJ Concepts (R) total joint prostheses Part III - Pain and dysfunction outcomes

47 end-stage TMJ patients with high occlusal plane angulation, treated with TMJ custom-fitted total joint prostheses and simultaneous maxillo-mandibular counter-clockwise rotation were evaluated for pain and dysfunction presurgery (T1) and at the longest follow-up (T2). Patients subjectively rated their facial pain/headache, TMJ pain, jaw function, diet and disability. Objective functional changes were determined by measuring maximum interincisal opening (MIO) and laterotrusive movements. Patients were divided according to the number of previous failed TMJ surgeries: Group 1 (0-1), Group 2 (2 or more). Significant subjective pain and dysfunction improvements (37-52%) were observed (<0.001). MIO increased 14% but lateral excursion decreased 60%. The groups presented similar absolute changes, but Group 2 showed more dysfunction at T1 and T2. For patients who did not receive fat grafts around the prostheses and had previous failure of proplast/teflon and or silastic TMJ implants, more than half required surgery for TMJ debridement and removal of foreign body giant cell reaction and heterotopic bone formation. End-stage TMJ patients can be treated in one operation with TMJ custom-made total joint prostheses and maxillo-mandibular counter-clockwise rotation, for correction of dentofacial deformity and improvement in pain and TMJ dysfunction; Group 1 patients had better results than Group 2 patients.

Tunnel technique with a surgical maneuver to increase the graft extension: Case report with a 3-year follow-up

Background: This article reports a clinical case with a 3-year follow-up in which a subepithelial connective tissue graft (SCTG) was used with the tunnel technique to treat multiple gingival recessions, and describes a technique used to enlarge the extension of the graft.Methods: A 41 -year-old female patient was referred for evaluation and treatment of maxillary multiple recessions. Following basic therapy, the plaque index was 23%, and the gingival index was 12%. Thus, SCTG with the tunnel technique was proposed to provide root coverage of Miller Class I recession on teeth #8 through #11 and a Miller Class III recession on tooth #12. After the donor area had been prepared, SCTG was removed and split cross-sectionally to lengthen it. The graft was placed through the tunnel and sutured.Results: Two weeks after the surgical procedure, the tissue color was nearly homogeneous with some reddish regions where the connective tissue was left uncovered, and there were no signs of incisions or suture marks. After 3 years of follow-up, the mean coverage of the recessions was 2.2 +/- 0.7 mm (74.2%), which corresponded to the gain of keratinized tissue. In addition, a gain in tissue thickness was observed.Conclusion: In a long-term evaluation, the tunnel technique with the elongated SCTG was used successfully for treatment of multiple gingival recessions with an increase of the soft tissue volume and gain of keratinized tissue.

Immediate reconstruction of frontal sinus fractures: review of 26 cases

Purpose: the purpose of this study was to evaluate complications occurring after immediate reconstruction of severe frontal sinus fractures, including cases where the fracture was not limited to the anterior wall and also involved the posterior wall and/or sinus floor.Patients and Methods: the records of twenty-six patients presently undergoing follow-up for frontal sinus fracture reconstruction were reviewed. Information regarding demographics, fracture characteristics and causes, associated facial fractures, use of grafts or implants, type of fixation used, nasofrontal duct management, use of antibiotics, and complications were noted. Patients were asked to return for clinical and radiographic follow-up to access late complications.Results: the average age of patients with frontal fractures was 29.1 years and 92.3% were male. Mean follow-up was 3.6 years. The most common causes of fracture were motor vehicle accidents and physical aggression. All patients presented with comminuted and dislocated anterior wall fractures, 34.6% presented with posterior wall fractures, and 46% had sinus floor fractures. Complications occurred in 7 patients (26.92%) and included pneumoencephalus, frontal cutaneous fistula, frontal bone irregularity, and sinusitis.Conclusions: Frontal sinus reconstruction is a good procedure for immediate fracture treatment if there is not excessive comminution, dislocation, or instability of the posterior wall and if the frontonasal duct area is intact or can be repaired. Most complications result from incorrect indication for reconstruction. (C) 2004 American Association of Oral and Maxillofacial Surgeons.

Inside-out vein graft and inside-out artery graft in rat sciatic nerve repair

Although veins and arteries present similar wall structures, there are differences which may be relevant in peripheral nerve reconstruction. Inside-out vein grafts (IOVG) have been satisfactorily used to repair both motor and sensitive nerves. However, the inside-out artery graft (IOAG) is a new technique and not fully investigated. Our study presents comparative morphological data on nerve regeneration achieved with IOVG and IOAG in the repair of Wistar rat sciatic nerves. Jugular veins and aorta arteries were harvested from donor animals and used inside-out to bridge a 10-mm gap. Animals were sacrificed at 10 weeks to evaluate nerve regeneration. Both techniques presented great variability in nervous tissue, though some animals showed satisfactory results. Different intensities of scarring processes might have interfered with nerve regeneration. Although IOVG and IOAG techniques showed similar morphometric results, in general, IOVG presented a closer-to-normal nerve organization than IOAG.

Nest architecture and population dynamics of the Ponerinae ant, Ectatomma opaciventre Roger (Hymenoptera : Formicidae)

Eleven nests of Ectatomma opaciventre were collected from January to December, 1994, in Rio Claro, SP, southeastern Brazil. This species excavates their nests up to 68 cm deep, containing 3, 4 or 5 chambers. The hole of entrance has a chimney-like rigid structure, with up to 2/5 cm high. The most numerous colonies were found in January and February, with 47 and 62 adult ants, respectively. The quantity of individuals decreased from March, being observed colonies with only 9 adult ants in June and July. The colony population increased again since September. Reproductive forms (winged ants) were observed between October and February. We did not observed immature stages in July, but they were numerous between September and March. There was a significant correlation between the number of colony individuals and temperature, but not between the number of colony individuals and relative humidity and rainfall. E. opaciventre is a species of hunter ants which have not an efficient recruitment system for food collecting, consequently their colonies are small due to the scarcity of food resources during the colder and dry months.

Influence of Osteopenia in Autogenous Bone Graft Healing With or Without Expanded Polytetrafluoroethylene Membranes: Histologic and Histomorphometric Study in Rats

Purpose: The aim of this study was to quantitatively evaluate and qualitatively describe autogenous bone graft healing with or without an expanded polytetrafluoroethylene (e-PTFE) membrane in ovariectornized rats. Materials and Methods: Eighty Wistar rats, weighing approximately 300 g each, were used. A graft was obtained from the parietal bone and fixed to the sidewall of each animal's left mandibular ramus. The animals were randomly divided into four experimental groups (n = 20 in each group): group 1, sham operated and autogenous bone graft only- group 2, sham operated and autogenous bone graft covered by e-PTFE membrane; group 3, ovariectornized (OVX) and autogenous bone graft only- group 4, OVX and autogenous bone graft covered by e-PTFE membrane. The animals were sacrificed at five different time points: immediately after grafting or at 7, 21, 45, or 60 days after grafting. Histologic examination and morphometric measurement of the sections were performed, and values were submitted to statistical analyses. Results: Both groups (sham and OVX) experienced loss of the original graft volume when it was not covered by the membrane, whereas use of the membrane resulted in additional bone formation beyond the edges of the graft and under the membrane. Histologic analysis showed integration of the grafts in all animals, although a larger number of marrow spaces was found in OVX groups. Conclusions: Association of bone graft with an e-PTFE membrane resulted in maintenance of its original volume as well as formation of new bone that filled the space under the membrane. Osteopenia did not influence bone graft repair, regardless of whether or not it was associated with e-PTFE membrane, but descriptive histologic analysis showed larger numbers of marrow spaces in the bone graft and receptor bed and formation of new bone in the OVX animals. INT J ORAL MAXILLOFAC IMPLANTS 2009;24:1074-1082

Desenvolvimento, produtividade e sobrevivência de maracujazeiro-amarelo enxertado e cultivado em área com histórico de morte prematura de plantas

O objetivo deste trabalho foi avaliar o desenvolvimento vegetativo, a produtividade e a sobrevivência do maracujazeiro-amarelo (Passiflora edulis Sims) enxertado sobre três porta-enxertos, em área com histórico de morte prematura de plantas. O experimento foi conduzido no município de Adamantina-SP, no período de maio de 2006 a fevereiro de 2007, adotando-se o delineamento de blocos ao acaso, com três tratamentos e sete repetições. Os porta-enxertos avaliados foram Passiflora edulis, P. alata e P. gibertii, utilizando-se da enxertia convencional por garfagem tipo fenda cheia. Avaliaram-se o diâmetro do caule do porta-enxerto e do enxerto, o comprimento do entrenó e dos ramos secundários, o número de ramos terciários e o de frutos, a massa média, o diâmetro e o comprimento médio dos frutos, a produtividade e a sobrevivência de plantas. Os resultados demonstraram que o uso da enxertia no maracujazeiro é uma opção viável como meio de propagação vegetativa, assim como forma de controle de alguns patógenos habitantes do solo, um dos problemas que têm limitado a expansão da cultura. As plantas enxertadas sobre P. edulis apresentaram melhor desenvolvimento inicial, seguido de P. gibertii e de P. alata. A menor produtividade ocorrreu em plantas sobre P. alata. Mesmo com a presença de Fusarium solani e Rotylenchulus reniformis nos solos, 91% das plantas enxertadas sobre P. gibertii sobreviveram após 12 meses de plantio no campo, enquanto em P. alata e P. edulis, esses índices foram de 60% e 8,6%, respectivamente, mostrando assim a maior tolerância às doenças causadas por patógenos habitantes do solo por P. gibertii.

Análises macro e microscópicas de enxertos cutâneos por semeadura após laserterapia de baixa intensidade

OBJETIVO: observar se a laserterapia de baixa intensidade acelera o processo inflamatório, a cicatrização e epitelização de enxertos cutâneos por semeadura. MÉTODOS: vinte ratos foram submetidos a esta técnica de enxertia e divididos em dois grupos iguais, um tratado com laser e outro controle. RESULTADOS: houve menor tempo de reação inflamatória, maior velocidade de cicatrização, epitelização e queratinização nos animais tratados com laser em relação aos não tratados. CONCLUSÃO: a laserterapia de baixa intensidade é efetiva no auxílio ao tratamento de enxertos por semeadura.

Aspectos clínicos e imunopatológicos da ceratoplastia com membrana amniótica xenógena fresca e conservada em glicerina: estudo experimental em coelhos

Avaliaram-se, por meio da análise clínica, histopatologia e imunoistoquímica, os efeitos da aplicação da membrana amniótica xenógena fresca e conservada em glicerina, sobre os mecanismos imunológicos da superfície ocular. Para tal, utilizaram-se 40 coelhos, distribuídos em dois grupos experimentais, os quais foram avaliados por 21 dias. A avaliação clínica revelou que a membrana amniótica xenógena conservada em glicerina estimulou uma resposta inflamatória aguda maior que a membrana aplicada fresca. A análise histopatológica indicou que ambas se comportaram de forma semelhante a partir da primeira semana de pós-operatório, apresentando as alterações clássicas da resposta inflamatória da córnea, com o predomínio de infiltrado do tipo polimorfonuclear. A análise imunoistoquímica indicou que, ainda aos 21 dias, a resposta imune local é inespecífica, permitindo concluir que a resposta imune específica na córnea é tardia e que a córnea é um sítio privilegiado para aplicação de enxertos com características imunológicas diferentes, visto que não houve o estímulo para o desenvolvimento de uma resposta mais específica nos grupos avaliados durante toda a execução do experimento.

Galea and periosteum flap filled with bone fragments in rabbits

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

Função osteoindutora de fragmentos ósseos conservados em glicerina a 98%: estudo experimental em ratos

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