Effect of different low-level intensity laser therapy (LLLT) irradiation protocols on the osseointegration of implants placed in grafted areas

Objective: To evaluate the effect of different protocols of low-level intensity laser therapy (LLLT) irradiation on the osseointegration of implants placed in grafted areas. Methodology: 84 rats were randomly allocated into six groups: DBB: defect filled with deproteinized bovine bone; HA/TCP: defect filled with biphasic ceramic of hydroxyapatite/β-tricalcium phosphate ; DBB-LI: defect filled with DBB and treated with LLLT after implant placement; HA/TCP-LI: defect filled with HA/TCP and treated with LLLT after implant placement; DBB-LIB: defect filled with DBB and treated with LLLT after graft procedure and implant placement; and HA/TCP-LIB: defect filled HA/TCP and treated with LLLT after graft procedure and implant placement. The bone defects were made in the tibia and they were grafted. After 60 days, the implants were placed. The rats were subsequently subjected to euthanasia 15 and 45 days after implant placement. The pattern of osseointegration and bone repair in the grafted area was evaluated by biomechanical, microtomographic, and histometric analyses. Furthermore, the expression of bone biomarker proteins was assessed. Results: The LLLT groups presented higher removal torque, mineralized tissue volume, and a greater degree of osseointegration, especially when LLLT was performed only after implant placement, and these findings were associated with higher expression of BMP2 and alkaline phosphatase. Conclusion: LLLT performed on implants placed in grafted areas enhances the osseointegration process

Effect of avocado/soybean unsaponifiables on periodontal repair in rats with arthritis and induced periodontitis

Objective: This study aimed to evaluate the effect of avocado/soybean unsaponifiables (ASU) on periodontal repair in rats with induced periodontitis and arthritis. Methodology: Forty-five rats were submitted to periodontitis induction by insertion of ligatures into the upper second molars, maintained for 15 days. These animals were randomly allocated to 3 groups according to the presence of induced arthritis (ART) and the application of the ASU: Control (CTR) group-healthy animals, where saline solution was administered; ART-animals with induced arthritis, where saline solution was administered; ART/ASU-animals with induced arthritis, where ASU (0.6 mg/ kg) was administered. The drugs were administered daily by gavage and the animals were euthanized after 7, 15 and 30 days of the ligature removal. Bone resorption, inflammatory infiltrate composition and marker proteins expression of the differentiation and formation of osteoclasts (RANKL and TRAP) were assessed. Results: The ART/ASU group presented higher bone volume than the ART group at 7 and 30 days after the ligature removal. Furthermore, the ART group presented higher quantity of inflammatory cells and expression of TRAP and RANKL than the other groups. Conclusion: ASU administration improves the repair of periodontal tissues in an experimental periodontitis model in rats with induced arthritis

Influence of Different Proportions of External Irrigation During the Er,Cr:YSGG Laser Irradiation on Wear and Roughness of Root Surface

Introduction: The aim of this study was to evaluate the influence of different levels of external irrigation during irradiation with an erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser on the roughness and wear of dental tissue during scaling procedures.Methods: Twenty-Five uniradicular bovine teeth had the proximal surfaces planed and divided into 3 regions: upper, middle and lower. The upper region was treated with hand instruments, the middle region was not treated and served as a control, and the lower region was treated by the Er,Cr:YSGG laser. The teeth were randomly divided into five groups according to the different proportions of external irrigation used during the laser irradiation: G1: 10%; G2: 20%; G3: 30%; G4: 40% and G5: 50%. The samples were analyzed for roughness and wear on the root surface irradiated with the laser.Results: There were no differences in the surface roughness and wear parameters between the groups irradiated with the laser, but the laser irradiation produced a rougher surface of the dentin than treatment with hand scaling.Conclusion: Changes in the external irrigation level did not influence the wear and roughness of root surfaces treated with an Er,Cr:YSGG lase

Biomateriais a base de quitosana na correção de defeitos ósseos críticos criados em calvaria de ratos: avaliação radiográfica

OBJETIVO: Este estudo avaliou através de imagens radiográficas digitais, a ação de biomateriais de quitosana e de cloridrato de quitosana, com baixo e alto peso molecular, utilizados na correção de defeitos ósseos de tamanho crítico (DOTC)em calvária de ratos. MATERIAL E MÉTODO: DOTCs com 8 mm de diâmetro foram criados cirurgicamente na calvária de 50 ratos Holtzman. Em 10 animais o defeito foi preenchido foram preenchidos com coágulo sanguíneo (controle negativo). Os 40 animais restantes foram divididos de acordo com o biomaterial utilizado no preenchimento do defeito (quitosana de baixo peso e de alto peso molecular, e cloridrato de quitosana de baixo e de alto peso molecular), e foram avaliados em dois períodos experimentais (15 e 60 dias), totalizando 5 animais/biomaterial/período de avaliação. RESULTADO: A avaliação radiográfica foi feita utilizando duas radiografias digitais do crânio do animal: uma tomada logo após o defeito ósseo ser criado e a outra no momento do sacrifício. Nessas imagens, foi avaliada a densidade óssea radiográfica inicial e a final na área do defeito, que foram comparadas. As análises na densidade óssea radiográfica indicaram aumento da densidade óssea radiográfica dos DOTCs tratados para todos os biomateriais testados, em ambos os períodos. Resultados semelhantes foram encontrados no grupo controle. CONCLUSÃO: Conclui-se que os biomateriais de quitosana testados não foram capazes de aumentar a densidade radiográfica em DOTC realizados em calvária de ratos

Reparo ósseo induzido por diferentes substitutos de enxerto ósseo em defeitos de tamanho crítico na calvária de ratos.

Introduction: The use of bone substitutes in grafting procedures as an alternative of the use of autogenous bone graft has been indicated, however, the direct comparison between these biomaterials has been little explored. Objective: To evaluate the effect of different osteoconductive bone substitutes on the bone repair in critical-sized defects (CSDs) in rat calvaria. Material and method: One CSD with an 8 mm diameter was made in each of the 40 rats used in this study. The animals were randomly allocated into 5 groups (n=8), according to the type of bone substitute used to fill the CSD: COA (Coagulum); AUT (autogenous bone); DBB (deproteinized bovine bone graft); HA/TCP (biphasic ceramic composed of hydroxyapatite and β-phosphate tricalcium); and TCP (β-phosphate tricalcium). A microtomographic analysis was performed to evaluate the remaining defect linear length (DLL) of the CSD and the volume of the mineralized tissues (MT) within the CSD at 3, 7, 15 and 30 days after the surgical procedure. In addition, a histometric analysis was performed to evaluate the composition of the repaired bone tissue (% Bone and % Biomaterial) at the 30-day period. Result: It was shown that the COA had the lowest DLL and MT within the CSD. In addition, the COA presented the highest % of bone in CSD. The DBB had a higher MT and a higher % of bone substitute particles in the CSD than the AUT and TCP groups. The DBB and AUT groups presented higher % of bone in the CSD than the TCP group. Conclusion: The use of the DBB promoted a better pattern of bone volume gain and formation compared to TCP and HA / TCP but was biologically inferior to the AUT.Introdução: A utilização de substitutos ósseos em procedimentos de enxertia como alternativa ao uso de enxerto ósseo autógeno tem sido indicada, entretanto, a comparação direta entre esses biomateriais tem sido pouco explorada. Objetivo: Avaliar o efeito de diferentes substitutos ósseos osteocondutores no reparo ósseo em defeitos de tamanho crítico (DAC) em calvária de ratos. Material e método: Um DSC com diâmetro de 8 mm foi feito em cada um dos 40 ratos usados ​​neste estudo. Os animais foram alocados aleatoriamente em 5 grupos (n = 8), de acordo com o tipo de substituto ósseo utilizado para o preenchimento do DSC: COA (Coágulo); AUT (osso autógeno); DBB (enxerto ósseo bovino desproteinizado); HA / TCP (cerâmica bifásica composta por hidroxiapatita e β-fosfato tricálcico); e TCP (β-fosfato tricálcico). Uma análise microtomográfica foi realizada para avaliar o comprimento linear do defeito remanescente (DLL) do DSC e o volume dos tecidos mineralizados (TM) dentro do DSC aos 3, 7, 15 e 30 dias após o procedimento cirúrgico. Além disso, foi realizada uma análise histométrica para avaliar a composição do tecido ósseo reparado (% Osso e% Biomaterial) no período de 30 dias. Resultado: Foi demonstrado que o COA apresentou o menor DLL e MT dentro do CSD. Além disso, o COA apresentou o maior% de osso na DAG. O DBB apresentou maior MT e maior% de partículas de substituto ósseo no CSD do que os grupos AUT e TCP. Os grupos DBB e AUT apresentaram maior% de osso no DSC do que o grupo TCP. Conclusão: O uso do DBB promoveu melhor padrão de ganho e formação de volume ósseo em relação ao TCP e HA / TCP, mas foi biologicamente inferior ao AUT

Minimally Invasive Surgery for Clinical Crown Lengthening Using Piezoelectric Ultrasound

This case report is aimed at describing a flapless, minimally invasive clinical crown lengthening with an osteotomy performed using a piezoelectric ultrasound. A female patient complained about the amount of gum that was exposed when she smiled, which caused aesthetic discomfort. After a clinical examination, it was confirmed that the patient had excessive gum exposure in the upper arch of the dental region for teeth 14 to 24 when she smiled. The tomographic exam showed that bone tissue was at the level of the enamel-cementum junction, and gingival tissue covered a part of the anatomic crown. Virtual analysis using digital smile design (DSD) demonstrated that enlarging the clinical crowns would provide better aesthetics. The excess gingival tissue was removed from the gingival margin region with the aid of a mockup without interference to the interdental papillae. Then, osteotomy was performed using piezoelectric ultrasound until there was a 2.5 mm distance from the top of the bone crest to the new gingival margin. In the postoperative period, good repositioning of the gingival margin, absence of postoperative complications, and rapid healing of the gingival tissue were verified. After 6 months, a good aesthetic outcome was observed with stability in the level of the periodontal tissues obtained via the crown-lengthening technique. It can be concluded that the minimally invasive clinical crown-lengthening technique was effective in repositioning the gingival margin with no postoperative complications

Strontium-loaded Deproteinized Bovine Bone Grafting in Rat Calvarial Critical-sized Defects

Objectives: To evaluate bone healing after grafting critical-sized calvarial defects (CSD) in rats with strontium-loaded deproteinized bovine bone (DBB). Methods: One circular full-thickness bone defect (Ø 5mm) was prepared on each parietal bone of 42 female wistar rats. One of the defects was left empty as negative control and the other was grafted with either: 1) DBB loaded with 140Μm of Sr per gr biomaterial (DBB/Sr1); or 2) DBB loaded with 700Μm of Sr per gr biomaterial (Group DBB/Sr2); or 3) DBB soaked with sterile saline (DBB/NaCl), to achieve 3 equally-sized groups. Groups of 7 animals were sacrificed after 15 and 60 days post-surgery. Analyses included microCT evaluation of residual defect length and %mineralized tissue and histomorphometric evaluation of %bone, %DBB, and %other tissues within the defect. Differences among the 3 treatment groups were evaluated with One-way Anova and post-hoc Tukey test, while differences between grafted and non-grafted defect within each group were evaluated with the paired t-test; the level of significance was set at P < 005. Results: At 15 days of healing, newly formed bone was in general limited in both grafted and non-grafted defects, irrespective treatment group; DBB/Sr2 presented shorter residual defect length (p<0.05) and larger %mineralized tissue within the defect (p<0.01) compared to the DBB/NaCl group. At 60 days, DBB/Sr2 presented shorter residual defect length and larger %mineralized tissue within the defect than the DBB-Sr1 (p<0.001 and <0.001, respectively) or the DBB/NaCl (p<0.05 and <0.001, respectively) group. Further, DBB/Sr grafted defects showed statistically significant larger %bone (DBB/Sr2: 8.7±0.9, DBB/Sr1: 8.3±1.1; p<0.05) comparing to DBB/NaCl grafted defects (6.9±0.6). %DBB was similar among groups at all experimental periods. DBB grafted defects presented consistently with lower %bone than empty controls (range: 6.9 – 8.7% versus 14.0 – 20.2%, respectively), irrespective treatment group or observation period (p < 0.001). Conclusions: Strontium-loaded DBB grafting in rat calvarial critical-sized defects enhanced bone formation comparing to grafting with DBB/NaCl