Impact of a modified implant macrogeometry on biomechanical parameters and bone-related markers in rats

Abstract This study investigated the impact of a modified implant macrogeometry on peri-implant healing and its effect on bone-related molecules in rats. Eighteen rats received one implant in each tibia: the control group received implants with conventional macrogeometry and the test group received implants with modified macrogeometry. After 30 days, the implants were removed for biomechanical analysis and the bone tissue around them was collected for quantifying gene expression of OPN, Runx2, β-catenin, BMP-2, Dkk1, and RANKL/OPG. Calcein and tetracycline fluorescent markers were used for analyzing newly formed bone at undecalcified sections of the tibial implants. These fluorescent markers showed continuous bone formation at cortical bone width and sparse new bone formed along the medullary implant surface in both groups. However, higher counter-torque values and upregulation of OPN expression were achieved by test implants when compared to controls. The modified macrogeometry of implants optimized peri-implant healing, favoring the modulation of OPN expression in the osseous tissue around the implants.

Does resveratrol favor peri-implant bone repair in rats with ovariectomy-induced osteoporosis? Gene expression, counter-torque and micro-CT analysis

Abstract This study investigated the influence of resveratrol on peri-implant repair and its effects on bone-related markers in ovariectomy-induced osteoporosis in rats. Animals were divided into: OVX+PLAC (n = 10): ovariectomized animals treated with placebo; OVX+RESV (n = 10): OVX treated with resveratrol; OVX+PLAC+ZOL (n = 10): OVX treated with PLAC and zoledronate; OVX+RESV+ZOL (n = 10): OVX treated with RESV and ZOL; and SHOVX+PLAC (n = 10): sham ovariectomy treated with PLAC. RESV and PLAC were administrated after ovariectomy and ZOL after six weeks after OVX, until the end of experiment. One implant was inserted in each tibiae of animals 18 weeks after ovariectomy. After 4 weeks, one implant was removed for counter-torque, and peri-implant tissue was collected for mRNA quantification of several osteogenic markers by PCR. The other tibia was submitted to micro-computed tomography analysis. Reduced counter-torque values, bone-implant contact (BIC) and bone volume fraction (BV/TV), and higher bone porosity (BP) were detected in OVX+PLAC group when compared to SHOVX+PLAC (p < 0.05). OVX+RESV rats presented lower BIC, BV/TV, and trabecular number (Tb.N), and augmented BP and trabecular spacing (Tb.Sp) when compared to SHOVX+PLAC (p < 0.05). Higher Tb.N and connectivity density (Conn.Dn) and reduced Tb.Sp were observed in OVX rats treated with ZOL, independently of RESV, when compared to OVX+PLAC and OVX+RESV groups (p < 0.05), whereas the combination ZOL+RESV promoted lower BP when compared to OVT+PLAC and OVX+RESV (p < 0.05). Gene expression was not influenced by RESV (p > 0.05), whereas ZOL promoted up-regulation of BMP-2 (p<0.05). RESV did not improve peri-implant bone repair in rats with ovariectomy-induced osteoporosis.

Impact of history of periodontitis on gene expression of bone-related factors in young patients

Abstract Although dental implants and bone regenerative procedures are important approaches for the reestablishment of esthetics and function in young patients with a history of generalized aggressive periodontitis (GAP), no predictable outcomes have been reported, and the host osteo-immunoinflammatory response may play a relevant role in this context. In view of the lack of molecular investigations into the bone tissue condition of young patients with periodontitis, the aim of this study was to evaluate the gene expression of bone-related factors in this population. Bone biopsies were obtained from the posterior mandible in 16 individuals previously diagnosed with GAP and on periodontal support therapy and from 17 periodontally healthy (PH) patients. The gene expression of tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, receptor activator of the NF-κB ligand (RANKL), osteoprotegerin (OPG), osteocalcin (OC), bone sialoprotein (BSP), and type I collagen (COL-I), important biomarkers of bone turnover, was evaluated by qRT-PCR. Lower TGF-β and OPG mRNA levels were observed in GAP patients compared to PH individuals (p ≤ 0.05). There were no between-group differences in levels of TNF-α, BSP, RANKL, OC, or COL-I mRNA (p>0.05). In young adults, a history of periodontal disease can negatively modulate the gene expression of important bone-related factors in alveolar bone tissue. These molecular outcomes may contribute to the future development of therapeutic approaches to benefit bone healing in young patients with history of periodontitis via modulation of osteo-immuno-inflammatory biomarkers.

Host response and peri-implantitis

Abstract Considering the absence of predictable and effective therapeutic interventions for the treatment of peri-implantitis, scientific evidence concerning the host response profile around dental implants could be important for providing in the future a wider preventive and/or therapeutic window for this peri-implant lesion, indicating biomarkers that provide quantifiable measure of response to peri-implant therapy. Moreover, a better knowledge of pattern of host osteo-immunoinflammatory modulation in the presence of peri-implantitis could either benefit the early diagnostic of the disease or to cooperate to prognostic information related to the status of the peri-implant breakdown. Finally, new evidences concerning the host profile of modulators of inflammation and of osseous tissue metabolism around dental implants could explain the individual susceptibility for developing peri-implant lesions, identifying individuals or sites with increased risk for peri-implantitis. The focus of this chapter was, based on a systematically searched and critically reviewed literature, summarizing the existing knowledge in the scientific research concerning the host osteo-immunoinflammatory response to the microbiological challenge related to periimplantitis.

Doença periodontal e artrite idiopática juvenil: uma inter-relação bidirecional / Periodontal disease and juvenile idiopathic arthritis: a bidirectional inter-relationship

Parece haver similaridades entre a patogenia de doenças reumatológicas (artrite reumatoide e artrite idiopática juvenil) e periodontite. Alguns estudos têm sido conduzidos com o objetivo de elucidar os mecanismos que explicam a inter-relação entre essas condições. A artrite reumatoide parece aumentar a suscetibilidade à doença periodontal destrutiva em adultos e em pacientes com artrite idiopática juvenil. No entanto, ainda são pouco conhecidas as vias de associação entre essas condições crônicas infl amatórias (periodontite e artrite). Desta forma, o objetivo deste trabalho foi promover uma revisão da literatura sobre a inter-relação artrite idiopática infantil e doença periodontal.

Similarities between rheumatologic diseases (rheumatoid arthritis and juvenile idiopathic arthritis) and periodontitis pathogenesis are discussed. Some studies have been conducted to elucidate the mechanisms that explain the relationship between these conditions. Rheumatoid arthritis appears to increase susceptibility to destructive periodontal disease in adults and in patients with juvenile idiopathic arthritis. However, the pathway of association between these chronic infl ammatory conditions are barely known. Thus, the aim of this study was to review the literature concerning the relationship between juvenile idiopathic arthritis and periodontitis.

Aumento de coroa estético associado à reabilitação protética ­ relato de caso clínico / Aesthetic crown lengthening associated with prosthetic rehabilitation ­ a case report

Atualmente, a estética periodontal ou estética vermelha tem sido muito discutida e valorizada na busca pela harmonia do sorriso. Em situações de erupção passiva alterada, ou seja, existência de grande exposição de gengiva acompanhada de coroas clínicas curtas, há uma indicação precisa para a execução de aumento de coroa clínica. A Odontologia estética reabilitadora exerce um papel fundamental no tratamento multidisciplinar. Este trabalho teve como objetivo relatar um caso clínico de sorriso gengival causado pela erupção passiva alterada, associando reabilitação estética com facetas dentárias. Após a conclusão do tratamento, foi possível afirmar que a interação Prótese/Periodontia foi de fundamental importância para a obtenção do resultado final esperado pela paciente.

Nowadays, the periodontal or red esthetics has been highlightened in the search of smile harmony. In cases of altered passive eruption, which means the existence of great gum exhibition and short clinical crowns, there is precise indication for crown lengthening. Esthetic dentistry has a fundamental role in the multidisciplinary treatment. This paper reports on a clinical case of gummy smile due to passive eruption receiving an oral rehabilitation with laminate veneers. After treatment delivery, it was possible to recognize that the Prosthodontic/Periodontal relationship is of critical importance for the patient's desired outcome.

Evaluation of bone loss due to primary occlusal trauma in two experimental models of occlusal overload / Avaliação da reabsorção óssea promovida pelo trauma oclusal primário em dois modelos experimentais de sobrecarga oclusal

Introduction: Primary occlusal trauma (OT) is an injury of the periodontium with normal height as a result of occlusal forces which exceed their adaptive capacity. Objective: To evaluate, histometrically, the alveolar bone loss in the furcation region of rats experimentally submitted to 2 models of occlusal overload. Material and method: 45 animals randomly divided into 3 groups: Occlusal Interference (OI, n = 15) - fixing an orthodontic wire segment on the occlusal surface of the first lower molar; Occlusal Overload (OO, n = 15) - wearing of the cusps of the lower contralateral molars, the second and third molars next to the first molar that had its dimensions maintained; Negative Control (NC, n = 15) - evaluation of the initial dimensions of the periodontal ligament (PL). Five animals / group were sacrificed after 14, 21 and 28 days. Result: Intergroup evaluation showed significant bone loss in OI (p<0.001) and OO (p<0.01) compared to NC. OI had significantly higher bone loss compared to OO at 14 (p<0.01), 21 (p <0.01) and 28 days (p<0.01). The intragroup evaluation showed no significant influence of time on bone loss in OI and OO, regardless of the technique used (p>0.05). The thickness of the PL remained stable in NC (p>0.05). Conclusion: OI and OO were effective in the experimental reproduction of OT, and OI promoted greater alveolar bone loss compared to OO, showing that the impact of occlusal overload in OI increased the extent of the OT injury.

Introdução: Trauma oclusal primário (TO) é a injúria causada no periodonto de inserção de dentes com periodonto de altura normal devido a forças oclusais que excedem sua capacidade adaptativa. Objetivo: Avaliar histometricamente a reabsorção óssea alveolar na região da furca do 1º molar inferior em ratos submetidos experimentalmente a 2 modelos de sobrecarga oclusal. Material e método: 45 animais aleatoriamente divididos em 3 Grupos: Interferência Oclusal (GI, n = 15) - fixação de um segmento de fio ortodôntico na face oclusal do 1º molar inferior; Sobrecarga Oclusal (GS, n = 15) - desgaste das cúspides dos molares inferiores contralaterais e dos 2º e 3º molares do lado do 1º molar que teve suas dimensões mantidas; Grupo Controle Negativo (CN, n = 15) - avaliação das dimensões iniciais do ligamento periodontal. Cinco animais/grupo foram submetidos à eutanásia após 14, 21 e 28 dias. Resultado: A avaliação intergrupos mostrou que houve reabsorção óssea significativa em GI (p<0,001) e GS (p<0,01) quando comparados com CN. O grupo GI teve reabsorção óssea significativamente maior quando comparado ao grupo GS em 14 (p<0,01), 21 (p<0,01) e 28 dias (p<0,01). A avaliação intragrupos não mostrou influência significativa do tempo na reabsorção óssea em GI e GS, independente da técnica utilizada (p>0,05). A espessura do ligamento periodontal manteve-se estável no grupo CN (p>0,05). Conclusão: GI e GS foram eficazes na reprodução experimental do TO e GI promoveu maior reabsorção óssea alveolar quando comparado a GS, mostrando que o impacto causado pela sobrecarga oclusal no grupo GI aumentou a lesão por TO.

Avaliação da utilização da esponja de chitosan/tricálcio fosfato no reparo de defeitos ósseos em calvária de ratos: desenho split-mouth / Evaluation of a chitosan/tricalcium phosphate sponge on the repair of rat calvarial bone defects: split-mouth design

Objetivo: avaliar o efeito da esponja de chitosan/tricálcio fosfato, biopolímero natural não tóxico e biodegradável, no reparo de defeitos de tamanho crítico em calvária de ratos. Material e métodos: 20 ratos machos adultos (Wistar) receberam dois defeitos ósseos de tamanho crítico na região parietal (broca trefina 5 mm de diâmetro interno), sendo um dos defeitos preenchido com esponja de chitosan (grupo-teste) e o outro com osso autógeno particulado (grupo-controle positivo). Cortes histológicos foram executados após 60 dias. Resultados: nos defeitos preenchidos com o chitosan, observou-se média de 37,8% de remanescentes da esponja. Em uma análise linear destes defeitos, o preenchimento ósseo ocorreu em uma média de 0,57 ± 0,38 mm. Nos defeitos preenchidos com osso autógeno (controle positivo), foi registrada média de 5,02 mm de osso vital. Comparando os dois grupos experimentais em termos percentuais, observou-se que no grupo-teste o preenchimento com tecido ósseo foi menor do que no grupo-controle (7,8% e 68,8%), respectivamente (teste de Tukey, p < 0,001). Conclusão: a esponja de chitosan/tricálcio fosfato tem um efeito pequeno sobre o reparo ósseo em defeitos de calvária de ratos, quando comparada ao osso autógeno.

A deficiência de estrogênio e a osteoporose como paradigmas atuais em periodontia / Estrogen deficiency and osteoporosis as current paradigms in periodontology

A osteoporose é uma condição sistêmica que altera a homeostase do tecido ósseo, acarretando um débito mineral no indivíduo. Apesar de não ser considerada um fator de risco periodontal, a osteoporose pode intervir sobre o delineamento e a condução do plano de tratamento, uma vez que a afecção não é restrita aos ossos longos, mas também da maxila e da mandíbula, o que poderia influenciar a reabsorção óssea alveolar, acarretando um agravamento no impacto das lesões do periodonto de inserção por doença periodontal ou por trauma oclusal, assim como alterando ou limitando a reabilitação oral por implantes. É, portanto, de grande relevância clínica que o periodontista esteja familiarizado com essa doença e com as limitações que por ventura alterem o prognóstico do caso. Objetiva-se, com este trabalho de revisão, uma abordagem da literatura científica para que melhor sejam elucidados os fatores limitantes dessa doença osteometabólica dentro dos interesses da clínica periodontal.

Osteoporosis is a systemic disease which modifies bone homeostasis leading to mineral deficit. Even though it is not yet considered a periodontal risk factor, osteoporosis can influence clinical intervention because it affects not only long bones but also the maxilla and the mandible. This could increase alveolar bone resorption leading to worse periodontal lesions by periodontal disease and occlusal trauma. It also could change or limit rehabilitation with oral implants. Periodontist’s knowledge of this osteometabolic disease plays a major role in clinical success of osteoporotic patients because there may be situations in which periodontal rehabilitation and prognosis might be compromised. This review aims to approach scientific literature to better elucidate limitation factors of this osteometabolic disease inside clinical periodontal interests.