Avaliação tomográfica e histomorfométrica do uso da fibrina rica em plaquetas e leucócitos na cicatrização alveolar após extração dentária: um ensaio clínico randomizado / Tomographic and histomorphometric evaluation of socket healing after tooth extraction using leukocyte- and platelet-rich fibrin: a randomized, single-blind, controlled clinical trial

O uso dos concentrados plaquetários tem sido amplamente estudado em procedimentos cirúrgicos bucais. Entretanto ensaios clínicos randomizados com avaliação histomorfométrica e baixo risco de viés não são encontrados na literatura. Um ensaio clínico randomizado, controlado, cegado e paralelo foi conduzido para avaliar a eficácia da fibrina rica em plaquetas e leucócitos (L-PRF) na preservação alveolar após extrações dentárias. Adicionalmente, o efeito do L-PRF na formação óssea foi avaliado através de análises histomorfométricas. Espécimes de biópsias foram obtidos durante a cirurgia de instalação dos implantes dentários, três meses após a exodontia. Quarenta e oito pacientes com necessidade de exodontia de um elemento dentário, incluíndo pré-molares, caninos ou incisivos, foram aleatoriamente alocados em dois grupos, L-PRF (n=24) e controle (n=24). A análise por intenção de tratamento dos dados tomográficos revelou que o L-PRF reduziu a perda óssea horizontal 1mm e 3 mm abaixo da crista óssea alveolar. A perda óssea 1mm abaixo da crista foi de 0.93 ± 0.9 mm para o grupo do L-PRF e 2.27 ± 1.2 mm para o grupo controle (p=0.0001). A perda óssea 3mm abaixo da crista foi 0.85 ± 0.8 mm para o grupo L-PRF e 1.67 ± 1.1 mm para o grupo controle (p=0.005). Similarmente, o L-PRF reduziu a perda óssea vertical da tábua vestibular no grupo L-PRF, 0.70 ± 0.7 mm comparado ao grupo controle 1.39 ± 1.2 mm (p=0.02). A neoformação óssea volumétrica medida através de análise tomográfica foi significantemente maior no grupo L-PRF 190.90 ± 169.90mm3 comparada com o grupo controle 44.87 ± 200.20mm3 (p=0.009). A análise por intenção de tratamento dos dados histomorfométricos mostrou uma maior porcentagem de osso neoformado no grupo L-PRF comparado com o grupo controle, 55.96 ± 11.97% e 39.69 ± 11.13%, respectivamente (p=0.00001). Estes resultados indicam que o uso de L-PRF reduziu a reabsorção óssea alveolar após a extração dentária, e melhorou a qualidade do osso neoformado. Portanto devemos sempre considerar o uso de L-PRF quando a preservação alveolar estiver sendo planejada. (Clinicaltrials.gov NCT03408418)(AU)

The use of platelet concentrate in alveolar ridge preservation has been broadly studied in oral surgical procedures. However, no randomized clinical trial with histomorphometric analysis and low risk of bias are available in the literature. We conducted a prospective, single-blind, parallel, randomized, controlled clinical trial to evaluate the efficacy of leukocyte- and platelet-rich fibrin (L-PRF) in socket preservation after tooth extraction. Additionally, the effect of L-PRF on bone formation was analyzed histologically using bone biopsy specimens obtained during implant placement. A total of 48 subjects who underwent a non-molar tooth extraction were randomly assigned to the L-PRF group (n=24) or the control group (n=24). Cone-beam computed tomographies were performed immediately after tooth extraction and at 3 months after tooth extraction, prior to implant surgery. The intention-to-treat analysis of data from tomographies showed that L-PRF reduced horizontal bone loss at 1 mm below the alveolar crest, means of 0.93 ± 0.9 mm for the L-PRF group and 2.27 ± 1.2 mm for the control group (p=0.0001), and at 3 mm below the alveolar crest, means of 0.85 ± 0.8 mm for the L-PRF group and 1.67 ± 1.1 mm for the control group (p=0.005). Similarly, L-PRF reduced vertical bone loss at the buccal bone wall, means of 0.70 ± 0.7 mm for the L-PRF group and 1.39 ± 1.2 mm for the control group (p=0.02). The mean value of new bone formation in the L-PRF group (190.90 ± 169.90mm3) was significantly higher when compared with the control group (44.87 ± 200.20mm3) p=0.009. Histomorphometric analysis showed a higher percentage of new bone formation in the L-PRF group compared with the control group. The values were 55.96 ± 11.97% and 39.69 ± 11.13%, respectively (p=0.00001). These findings indicate that the administration of L-PRF reduce the bone resorption after tooth extraction and improve the new bone formation. Therefore it should always be considered when socket preservation is planned (Clinicaltrials. gov NCT03408418)(AU)

Evaluation of the effect of platelet-rich plasma on alveolar wound healing in rats / Evaluación del efecto del plasma rico en plaquetas en la cicatrización de heridas alveolares en ratas

Opinions about the clinical utility of platelet-rich plasma (PRP) vary, as a large number of experimental studies have questioned its efficacy. The purpose of this study was to evaluate the effects of PRP on experimental alveolar wound healing in rats. Fifty young adult male Wistar rats were divided in control and PRP groups and submitted to extraction of the right maxillary incisor. In the PRP group, blood was collected by cardiac puncture, and the socket was filled with a PRP gel. Animals were euthanized after 1, 3, 7, 14 and 30 days. Histological and histomorphometric analyses were performed at each experimental time point. Semiquantitative histological analysis showed that the PRP group exhibited significantly more collagen-matrix deposition and less bone-matrix formation in the socket than did the control group from 7 to 30 days. Histomorphometric analyses showed that the PRP group also exhibited lower bone-tissue areas than the control group at 7 (p=0.0250) and 14 days (p<0.0001), but at 30 days, no significant difference between the groups was observed. In the present study, PRP did not enhance alveolar wound healing, and PRP-treated rats exhibited low rates of bone deposition during the intermediate phases of alveolar socket repair.

Las opiniones sobre la utilidad clínica del plasma rico en plaquetas (PRP) varían, ya que un gran número de estudios experimentales han cuestionado su eficacia. El propósito de este estudio fue evaluar los efectos del PRP sobre la cicatrización experimental de heridas alveolares en ratas. Cincuenta ratas Wistar adultas fueron divididas en grupos control y PRP, y fueron sometidas a extracción del incisivo maxilar derecho. En el grupo de PRP, la sangre se recogió por punción cardiaca, y el alvéolo se llenó con un gel de PRP. Los animales se sacrificaron después de 1, 3, 7, 14 y 30 días. Se realizaron análisis histológicos e histomorfométricos en cada momento experimental. El análisis histológico semicuantitativo mostró que el grupo de PRP exhibió significativamente más deposición de matriz de colágeno y menos formación de matriz ósea en el receptáculo que el grupo control de 7 a 30 días. Los análisis histomorfométricos mostraron que el grupo PRP también exhibió áreas de tejido óseo inferiores al grupo control a 7 (p = 0,0250) y 14 días (p <0,0001), pero a los 30 días no se observó diferencia significativa entre los grupos. En el presente estudio, el PRP no mejoró la cicatrización de las heridas alveolares, y las ratas tratadas con PRP mostraron bajas tasas de deposición ósea durante las fases intermedias de la reparación de los receptáculos alveolares.

Experimental osteonecrosis: development of a model in rodents administered alendronate

Abstract The main objective of this study was to cause bisphosphonate-related osteonecrosis of the jaws to develop in a rodent model. Adult male Holtzman rats were assigned to one of two experimental groups to receive alendronate (AL; 1 mg/kg/week; n = 6) or saline solution (CTL; n = 6). After 60 days of drug therapy, all animals were subjected to first lower molar extraction, and 28 days later, animals were euthanized. All rats treated with alendronate developed osteonecrosis, presenting as ulcers and necrotic bone, associated with a significant infection process, especially at the inter-alveolar septum area and crestal regions. The degree of vascularization, the levels of C-telopeptide cross-linked collagen type I and bone-specific alkaline phosphatase, as well as the bone volume were significantly reduced in these animals. Furthermore, on radiographic analysis, animals treated with alendronate presented evident sclerosis of the lamina dura of the lower first molar alveolar socket associated with decreased radiographic density in this area. These findings indicate that the protocol developed in the present study opens new perspectives and could be a good starting model for future property design.

Alveolar ridge conservation by early bone formation after tooth extraction in rabbits: a histomorphological study / Conservación de la cresta alveolar por formación ósea temprana después de la extracción dentaria en conejos: un estudio histomorfológico

Alveolar ridge volume loss is an irreversible process. To prevent this physiological event, which typically result in significant local anatomical changes in both the horizontal and the vertical dimension, some strategies are indicated to minimize the loss of ridge volume that typically follows tooth extraction. The purpose of this study was to evaluate if three different bone grafts could promote new bone formation in the alveolar socket following tooth extraction for the alveolar ridge conservation. First mandibular molars of male adults rabbits were extracted and the extraction sockets were randomly treated with three different bone grafts, one xenograft and two alloplastic grafts, and a group that received no treatment (blood clot). The extraction sockets of selected rabbits from each group were evaluated at 4, 6, or 8-week post-extraction. The results indicated that the extraction sockets treated with alloplastic graft (biphasic calcium phosphate) exhibited lamellar bone formation (6.5%) as early as four weeks after the extraction was performed. Moreover, the degree of new bone formation was significantly higher (P<0.05) in the extraction sockets treated with biphasic calcium phosphate at 8-week post-extraction than that in the other study groups. In this study, we demonstrated that the proposed animal model is useful to evaluate the bone formation after tooth extraction and the alveolar ridge conservation is feasible. The new bone formation and alveolar ridge preservation with bone graft after extraction of molar teeth, could result in the maintenance of sufficient bone volume to place an implant in an ideal restorative position without the need for ancillary implant site development procedures.

La pérdida de volumen cresta alveolar, es un proceso irreversible. Para evitar este evento fisiológico, que típicamente resulta en cambios anatómicos locales significativos, tanto en la dimensión horizontal y vertical, existen algunos procedimienos para reducir al mínimo la pérdida de volumen óseo que sigue típicamente a la extracción del diente. El propósito de este estudio fue evaluar si tres injertos óseos diferentes podrían promover la formación de hueso en el alveolo tras la extracción del diente para la conservación de la cresta alveolar. Los primeros molares mandibulares de conejos machos adultos fueron extraídos y los alvéolos post extracción fueron rellenados aleatoriamente con tres injertos óseos diferentes, uno de xenoinjerto y dos injertos aloplásticos, más un grupo que no recibió tratamiento (coágulo de sangre). Los alvéolos post extracción en los conejos seleccionados de cada grupo fueron evaluados a las 4, 6, o 8 semanas post-extracción. Los resultados indicaron que los alvéolos tratados con injerto aloplástico mostraron formación de hueso lamelar (6,5%) ya a las 4 semanas post extracción. Por otra parte, el grado de formación de hueso nuevo fue significativamente mayor (P<0,05) en los alvéolos tratados con fosfato de calcio bifásico en 8 semanas post-extracción que en los otros grupos de estudio. Demostramos que el modelo animal propuesto es útil para evaluar la formación de hueso después de la extracción del diente, y la conservación de la cresta alveolar es factible. La nueva formación de hueso y la preservación del reborde alveolar con injerto óseo después de la extracción de los dientes molares, podrían mantener un volumen de hueso suficiente para colocar un implante en una posición ideal para la posterior restauración, sin la necesidad de procedimientos de quirúrgicos anexos.

Effect of PDGF-BB, IGF-I Growth Factors and their Combination Carried by Liposomes in Tooth Socket Healing

This work evaluated the bone-forming potential of the platelet-derived growth factor isoform BB (PDGF-BB), insulin-like growth factor I (IGF-I), and mixed PDGF-BB/IGF-I delivered in liposomes compared with phosphate buffered saline (PBS), in the healing process of rat tooth sockets. One hundred and twelve Wistar rats were randomized into 7 groups of 16 animals each and were evaluated at 3, 7, 14 and 21 days after extraction of the maxillary second molars. The left sockets were treated with PBS (P), empty liposome (L), IGF-I in PBS (IP), IGF-I in liposome (IL), PDGF-BB in PBS (PDP), PDGF-BB in liposome (PDL) and both growth factors (GFs) together within liposomes (PDIL). The right sockets were filled with blood clot (BC). Histological and histomorphometric analyses were used to evaluate the formation of new bone and blood vessels. Immunohistochemistry was performed to evaluate the expression of osteocalcin and vascular endothelial growth factor (VEGF) during bone repair. Data were tested statistically using a Tukey's test according to a Dunn's analysis and Mann-Whitney U test followed by Kruskal-Wallis one-way analysis. Results were considered significant when p<0.05. A significantly higher percentage of bone trabeculae and a higher number of blood vessels were observed in the IL, PDL and PDIL groups (p<0.05). However, these GF-liposome groups had statistically similar results. Immunohistochemical assays first detected osteocalcin and VEGF expression at 3 days followed by a peak at 7 days. Lower immunoreactivity levels were observed in the BC, L, P, IP and PDP groups compared with the IL, PDL and PDIL groups (p<0.05). The results suggest that GFs carried by liposomes, either in isolated or mixed forms, enhanced the healing process in rat tooth sockets. The differential expression of the osteogenic markers VEGF and osteocalcin in the early phases of bone healing support these findings.

Este trabalho avaliou o potencial de formação óssea do fator de crescimento derivado de plaquetas na isoforma BB (PDGF-BB), fator de crescimento semelhante à insulina I (IGF-I), e a mistura PDGF-BB/IGF-I administrada em lipossomas comparando com tampão fosfato salino (PBS), no processo de cicatrização de alvéolos dentários de ratos. Cento e doze ratos Wistar foram distribuídos aleatoriamente em 7 grupos de 16 animais cada e foram avaliados aos 3, 7, 14 e 21 dias após a extração dos segundos molares maxilares. Os alvéolos esquerdos foram tratados com PBS (P), lipossomas vazios (L), IGF-I em PBS (IP), IGF-I em lipossomas (IL), PDGF-BB em PBS (PDP), PDGF-BB em lipossomas (PDL) e ambos os fatores de crescimento (GFs) em associação dentro de lipossomas (PDIL). Os alvéolos direitos foram preenchidos com coágulo sanguíneo (BC). As análises histomorfométrica e histológica foram utilizadas para avaliar a formação de novo osso e vasos sanguíneos. Imunohistoquímica foi realizada para avaliar a expressão de osteocalcina e o fator de crescimento endotelial vascular (VEGF) durante o reparo ósseo. Os dados foram testados estatisticamente utilizando o teste de Tukey em acordo com análise de Dunn e o teste Mann-Whitney U seguido pela análise de um passo de Kruskal-Wallis. Os resultados foram considerados significantes quando p<0,05. Uma percentagem altamente significativa de osso trabecular e alto número de vasos sanguíneos foram observados nos grupos IL, PDL e PDIL (p<0,05). Todavia, esses grupos lipossoma-GF tiveram resultados similares estatisticamente. Ensaios de imunohistoquímica inicialmente detectaram a expressão de osteocalcina e VEGF aos 3 dias, seguida por um pico aos 7 dias. Niveis mais baixos de imunorreatividade foram observados em BC, L, P, PI e PDP quando comparados com os grupos IL, PDL e PDIL (p<0,05). Os resultados sugerem que GFs carreados por lipossomas, na forma isolada ou em combinação, aceleram o processo de cicatrização em alvéolos dentários de rato. A expressão diferencial dos marcadores osteogênicos VEGF e osteocalcina, nas fases iniciais de cicatrização óssea, confirma esses achados.

Caracterização morfométrica e molecular do papel de citocinas pró e anti-inflamatórias no processo de reparo ósseo alveolar em condições homeostáticas e infecciosas / Morphometric and molecular characterization of the role of pro- and anti-inflammatory cytokines in alveolar bone repair process under homeostatic and infectious conditions

O metabolismo ósseo é influenciado por fatores endócrinos, genéticos, de crescimento, sistema RANK/RANKL/OPG, além de uma variedade de moléculas regulatórias, como as citocinas. Citocinas têm sido implicadas na patogênese de doenças ósseas, no entanto, ainda pouco se sabe sobre os mecanismos envolvidos na interação entre o sistema ósseo e imunológico no processo de reparo ósseo. O objetivo deste estudo foi caracterizar o papel de TNF-α e IL-10 no reparo ósseo alveolar em condições homeostáticas (controle [C]) e infecciosas (alveolite experimental [A]) pós exodontia em camundongos C57Bl/6 (WT), TNFp55KO e IL-10KO. Após a cirurgia nos grupos infectados foi induzida a alveolite por meio de isquemia do alvéolo e uma suspensão de secreção purulenta. As maxilas foram coletadas em 0h, 7, 14 e 21 dias após a extração do incisivo superior para análises histológica, histomorfométrica e molecular (RealTimePCR). Na análise histomorfométrica foram quantificados os parâmetros coágulo, células inflamatórias, fibras, fibroblastos, vasos sanguíneos, matriz óssea, osteoblastos, osteoclastos, e outros espaço do líquido intersticial e medula óssea. Na análise molecular (RealTimePCR) foram quantificados a expressão de fatores de crescimento, marcadores ósseos e de matriz extracelular, citocinas e quimiocinas envolvidos no processo. Os dados obtidos foram submetidos ao teste OneWay ANOVA seguido do teste de comparação múltipla de Tukey. Os resultados demonstraram que nos camundongos WT-C houve a formação inicial de coágulo (0 hora) com início da expressão de BMP2, BMP4, BMP7, TGFb1 and VEGFa que tiveram aumento gradativo com pico em 7 dias. A expressão de TNF-α e IL10 também tiveram seus picos aos 7 dias em paralelo com contagem de leucócitos, associado com a expressão de CCL2, CCL5 e CXCL1. Nos períodos seguintes houve uma diminuição inflamatória e o aumento de marcadores osteoblásticos/osteogênicos. A indução da alveolite experimental em WT-A resultou no aumento marcante...

Bone metabolism is influenced by endocrine, genetic and growth factors, RANK/RANKL/OPG system, besides a variety of regulatory molecules, such as cytokines. Cytokines have been implicated in pathogenesis of bone diseases, however, little is known about the mechanisms involved in the interaction between skeletal and immune system in the bone repair process. The objective of this study was characterized the role of TNF-α and IL-10 in alveolar bone repair under homeostatic (control [C]) and infectious (experimental alveolitis [A]) conditions in C57Bl/6 (WT), TNFp55KO and IL-10KO mice. After surgery, in infectious groups was induced by ischemia alveolitis the well and a suspension of pus. The maxillas were collected at 0h, 7, 14 and 21 days after extraction of the maxillary incisor for histologic, histomorphometric and molecular (RealTimePCR). In histomorphometric analysis parameters were measured clot, inflammatory cells, fibers, fibroblasts, blood vessels, bone matrix, osteoblast, osteoclast, and other space - the interstitial fluid and bone mar row. Molecular analysis (RealTimePCR) were quantified the expression of growth factors, bone markers and extracellular matrix, cytokines and chemokines involved in the process. The data were submitted to the OneWay ANOVA test followed by Tukey's multiple comparison test. The results showed that in WT-C initial clot formation (0 hours) with early expression of BMP2, BMP4, BMP7, and TGFb1 VEGFa who had gradual increase peaking in 7 days. The expression of TNF-α and IL10 also peaked at 7 days in parallel with leukocyte count, associated with CCL2, CCL5 and CXCL1. In late periods there were decrease of inflammation and markers osteoblastic / osteogenic increased. Induction of experimental alveolitis in WT resulted in a marked increase in expression of TNF-α accompanied by increased expression of CXCL1 and CCL5, increased leukocyte count and decreased of IL10 expression that peaked at 14d, besides prominent...

Caracterização morfométrica e molecular do papel de citocinas pró e anti-inflamatórias no processo de reparo ósseo alveolar em condições homeostáticas e infecciosas / Morphometric and molecular characterization of the role of pro- and anti-inflammatory cytokines in alveolar bone repair process under homeostatic and infectious conditions

O metabolismo ósseo é influenciado por fatores endócrinos, genéticos, de crescimento, sistema RANK/RANKL/OPG, além de uma variedade de moléculas regulatórias, como as citocinas. Citocinas têm sido implicadas na patogênese de doenças ósseas, no entanto, ainda pouco se sabe sobre os mecanismos envolvidos na interação entre o sistema ósseo e imunológico no processo de reparo ósseo. O objetivo deste estudo foi caracterizar o papel de TNF-α e IL-10 no reparo ósseo alveolar em condições homeostáticas (controle [C]) e infecciosas (alveolite experimental [A]) pós exodontia em camundongos C57Bl/6 (WT), TNFp55KO e IL-10KO. Após a cirurgia nos grupos infectados foi induzida a alveolite por meio de isquemia do alvéolo e uma suspensão de secreção purulenta. As maxilas foram coletadas em 0h, 7, 14 e 21 dias após a extração do incisivo superior para análises histológica, histomorfométrica e molecular (RealTimePCR). Na análise histomorfométrica foram quantificados os parâmetros coágulo, células inflamatórias, fibras, fibroblastos, vasos sanguíneos, matriz óssea, osteoblastos, osteoclastos, e outros espaço do líquido intersticial e medula óssea. Na análise molecular (RealTimePCR) foram quantificados a expressão de fatores de crescimento, marcadores ósseos e de matriz extracelular, citocinas e quimiocinas envolvidos no processo. Os dados obtidos foram submetidos ao teste OneWay ANOVA seguido do teste de comparação múltipla de Tukey. Os resultados demonstraram que nos camundongos WT-C houve a formação inicial de coágulo (0 hora) com início da expressão de BMP2, BMP4, BMP7, TGFb1 and VEGFa que tiveram aumento gradativo com pico em 7 dias. A expressão de TNF-α e IL10 também tiveram seus picos aos 7 dias em paralelo com contagem de leucócitos, associado com a expressão de CCL2, CCL5 e CXCL1. Nos períodos seguintes houve uma diminuição inflamatória e o aumento de marcadores osteoblásticos/osteogênicos. A indução da alveolite experimental em WT-A resultou no aumento marcante...

Bone metabolism is influenced by endocrine, genetic and growth factors, RANK/RANKL/OPG system, besides a variety of regulatory molecules, such as cytokines. Cytokines have been implicated in pathogenesis of bone diseases, however, little is known about the mechanisms involved in the interaction between skeletal and immune system in the bone repair process. The objective of this study was characterized the role of TNF-α and IL-10 in alveolar bone repair under homeostatic (control [C]) and infectious (experimental alveolitis [A]) conditions in C57Bl/6 (WT), TNFp55KO and IL-10KO mice. After surgery, in infectious groups was induced by ischemia alveolitis the well and a suspension of pus. The maxillas were collected at 0h, 7, 14 and 21 days after extraction of the maxillary incisor for histologic, histomorphometric and molecular (RealTimePCR). In histomorphometric analysis parameters were measured clot, inflammatory cells, fibers, fibroblasts, blood vessels, bone matrix, osteoblast, osteoclast, and other space - the interstitial fluid and bone mar row. Molecular analysis (RealTimePCR) were quantified the expression of growth factors, bone markers and extracellular matrix, cytokines and chemokines involved in the process. The data were submitted to the OneWay ANOVA test followed by Tukey's multiple comparison test. The results showed that in WT-C initial clot formation (0 hours) with early expression of BMP2, BMP4, BMP7, and TGFb1 VEGFa who had gradual increase peaking in 7 days. The expression of TNF-α and IL10 also peaked at 7 days in parallel with leukocyte count, associated with CCL2, CCL5 and CXCL1. In late periods there were decrease of inflammation and markers osteoblastic / osteogenic increased. Induction of experimental alveolitis in WT resulted in a marked increase in expression of TNF-α accompanied by increased expression of CXCL1 and CCL5, increased leukocyte count and decreased of IL10 expression that peaked at 14d, besides prominent...

Avaliação dos efeitos do Sistema Damon nas inclinações dentárias, dimensões dos arcos e suporte ósseo alveolar por meio da tomografia computadorizada de feixe cônico / Changes in arch dimensions, buccolingual inclinations and alveolar bony support during alignment using Damon MX: a CBCT study

Avaliação dos efeitos do Sistema Damon nas inclinações dentárias, dimensões dos arcos e suporte ósseo por meio da tomografia computadorizada de feixe cônico Este estudo objetivou analisar as alterações nas inclinações vestibulolinguais dos dentes, nas dimensões dos arcos e nas espessuras das tábuas ósseas vestibulares durante o alinhamento com Sistema Damon, como também identificar fatores pré-tratamento (espessura óssea inicial, larguras dos arcos, apinhamento) e alterações do tratamento (expansão dos arcos, vestibularização dos dentes) possivelmente associados. Vinte e dois adolescentes com dentadura permanente completa até primeiros molares, tratados sem extrações e apinhamento inicial mínimo de 4mm superior: -6,71mm (DP 2,99), inferior: -5,12mm (DP 2,03) foram escaneados por tomografia computadorizada de feixe cônico (TCFC) antes (T0) e após (T1) o alinhamento com o Sistema Damon. As dimensões dos arcos e as inclinações vestibulolinguais dos dentes foram avaliadas a partir das TCFC (T0 e T1) em modelos 3D e cortes multiplanares, enquanto o apinhamento foi mensurado nos modelos de estudo (T0). A spessura das tábuas ósseas vestibulares nos ¾ coronais e » apical da raiz dentária foram mensuradas por meio de imagens de tomográficas parassagitais (0,3mm de espessura) das duas fases T0 e T1, nas áreas de incisivos centrais superiores e de segundos pré-molares e primeiros molares superiores e inferiores. As variáveis foram submetidas ao teste de de Shapiro-Wilk para testar sua distribuição. As alterações de todas as variáveis de T0 para T1 foram comparadas por meio dos testes t pareado ou de Wilcoxon. A correlação entre as alterações das espessuras ósseas com os possíveis fatores associados foi verificada pelo coeficiente de correlação de Pearson ou teste de correlação de Spearman. O alinhamento com o Sistema Damon produziu expansões dos arcos associados à proclinação dos dentes e à redução na espessura óssea vestibular. As tábuas ósseas vestibulares tornaram-se...

This study aimed first to assess the changes in teeth buccolingual inclinations, arch dimensions, and buccal bony plate thicknesses occurred during the alignment phase using a self-ligating brackets system (Damon MX). Secondly, to identify pre-treatment (initial bone thickness, initial arch widths, initial crowding) or treatment parameters (amount of expansion, amount of buccal tipping) that could act as risk predictors for buccal bone reduction during orthodontic treatment. Twenty-two adolescents with complete permanent dentition until first molars, minimum initial crowding of 4mm - maxillary: -6.71 mm (SD 2.99), mandibular: - 5.12 mm (SD 2.03) - treated without extractions were scanned by cone beam computed tomography (CBCT) before (T0) and after (T1) alignment using Damon System. Arch dimensions and teeth buccolingual inclinations were evaluated by means of digital models and multiplanar reconstructed images both obtained from CBCT (T0 and T1), crowding was measured on study casts (T0). Alveolar buccal bone thickness overlying the ¾ coronal and the » apical of the root were measured in the areas of maxillary central incisors, as well as maxillary and mandibular premolars and first molars by means of cross-sectional images reconstructed with 0.3 mm thickness at T0 and T1, Distribution of the variables was verified by Shapiro-Wilks test. Changes in all variables from T0 to T1 were compared using paired t test or Wilcoxon test. The correlation between changes in bone thickness with its possible associated factors was assessed by Pearson correlation coefficient or Spearman correlation test. Alignment using Damon System produced substantial arch expansion associated with proclination of teeth and reduction in buccal bone thickness. The buccal bone plates overlying 25% of the mesiobuccal roots of the maxillary first molars became unmeasurable during the alignment phase. The reduction in the measurable buccal bone thickness, overlying...

Avaliação dos efeitos do Sistema Damon nas inclinações dentárias, dimensões dos arcos e suporte ósseo alveolar por meio da tomografia computadorizada de feixe cônico / Changes in arch dimensions, buccolingual inclinations and alveolar bony support during alignment using Damon MX: a CBCT study

Avaliação dos efeitos do Sistema Damon nas inclinações dentárias, dimensões dos arcos e suporte ósseo por meio da tomografia computadorizada de feixe cônico Este estudo objetivou analisar as alterações nas inclinações vestibulolinguais dos dentes, nas dimensões dos arcos e nas espessuras das tábuas ósseas vestibulares durante o alinhamento com Sistema Damon, como também identificar fatores pré-tratamento (espessura óssea inicial, larguras dos arcos, apinhamento) e alterações do tratamento (expansão dos arcos, vestibularização dos dentes) possivelmente associados. Vinte e dois adolescentes com dentadura permanente completa até primeiros molares, tratados sem extrações e apinhamento inicial mínimo de 4mm superior: -6,71mm (DP 2,99), inferior: -5,12mm (DP 2,03) foram escaneados por tomografia computadorizada de feixe cônico (TCFC) antes (T0) e após (T1) o alinhamento com o Sistema Damon. As dimensões dos arcos e as inclinações vestibulolinguais dos dentes foram avaliadas a partir das TCFC (T0 e T1) em modelos 3D e cortes multiplanares, enquanto o apinhamento foi mensurado nos modelos de estudo (T0). A spessura das tábuas ósseas vestibulares nos ¾ coronais e » apical da raiz dentária foram mensuradas por meio de imagens de tomográficas parassagitais (0,3mm de espessura) das duas fases T0 e T1, nas áreas de incisivos centrais superiores e de segundos pré-molares e primeiros molares superiores e inferiores. As variáveis foram submetidas ao teste de de Shapiro-Wilk para testar sua distribuição. As alterações de todas as variáveis de T0 para T1 foram comparadas por meio dos testes t pareado ou de Wilcoxon. A correlação entre as alterações das espessuras ósseas com os possíveis fatores associados foi verificada pelo coeficiente de correlação de Pearson ou teste de correlação de Spearman. O alinhamento com o Sistema Damon produziu expansões dos arcos associados à proclinação dos dentes e à redução na espessura óssea vestibular. As tábuas ósseas vestibulares tornaram-se...

This study aimed first to assess the changes in teeth buccolingual inclinations, arch dimensions, and buccal bony plate thicknesses occurred during the alignment phase using a self-ligating brackets system (Damon MX). Secondly, to identify pre-treatment (initial bone thickness, initial arch widths, initial crowding) or treatment parameters (amount of expansion, amount of buccal tipping) that could act as risk predictors for buccal bone reduction during orthodontic treatment. Twenty-two adolescents with complete permanent dentition until first molars, minimum initial crowding of 4mm - maxillary: -6.71 mm (SD 2.99), mandibular: - 5.12 mm (SD 2.03) - treated without extractions were scanned by cone beam computed tomography (CBCT) before (T0) and after (T1) alignment using Damon System. Arch dimensions and teeth buccolingual inclinations were evaluated by means of digital models and multiplanar reconstructed images both obtained from CBCT (T0 and T1), crowding was measured on study casts (T0). Alveolar buccal bone thickness overlying the ¾ coronal and the » apical of the root were measured in the areas of maxillary central incisors, as well as maxillary and mandibular premolars and first molars by means of cross-sectional images reconstructed with 0.3 mm thickness at T0 and T1, Distribution of the variables was verified by Shapiro-Wilks test. Changes in all variables from T0 to T1 were compared using paired t test or Wilcoxon test. The correlation between changes in bone thickness with its possible associated factors was assessed by Pearson correlation coefficient or Spearman correlation test. Alignment using Damon System produced substantial arch expansion associated with proclination of teeth and reduction in buccal bone thickness. The buccal bone plates overlying 25% of the mesiobuccal roots of the maxillary first molars became unmeasurable during the alignment phase. The reduction in the measurable buccal bone thickness, overlying...

Experimental alveolitis in rats: microbiological, acute phase response and histometric characterization of delayed alveolar healing

The pathogenesis of alveolitis is not well known and therefore experimental situations that mimic some features of this disease should be developed. OBJECTIVE: In this study, the evolution of the experimentally induced infection in rat sockets is characterized, which leads to clinical signs of suppurative alveolitis with remarkable wound healing disturbs. MATERIAL AND METHODS: Non-infected (Group I) and experimentally infected sockets in Rattus novergicus (Group II) were histometrically evaluated regarding the kinetics of alveolar healing. In addition, the characterization of the present bacteria in inoculation material and the serum levels of C-reactive protein (CRP) were performed. The detected species were Capnocytophaga ochracea, Fusobacterium nucleatum ss nucleatum, Prevotella melaninogenica, Streptococcus anginosus, Treponema socranskii and Streptococcus sanguis. RESULTS: All experimentally infected rats developed suppurative alveolitis, showing higher levels of CRP in comparison to those non-infected ones. Furthermore, infected rats presented a significant delayed wound healing as measured by the histometric analysis (higher persistent polymorphonuclear infiltrate and lower density of newly formed bone). CONCLUSION: These findings indicate that rat sockets with experimentally induced infection produced higher levels of serum CRP, showing the potential of disseminated infection and a disturb in the alveolar repair process in an interesting experimental model for alveolitis studies.

Comparison of two methods for alveolar bone loss measurement in an experimental periodontal disease model in rats

There are many studies that evaluate possible risk factors for periodontal diseases in animals. Most of them have focused only on the biological aspects of disease occurrence; therefore, it has been difficult to compare studies of the different methodological approaches. The aim of the present study was to compare different methods - linear and area - of the evaluation of morphometrical alveolar bone loss. Sixty hemimaxillae, defleshed and stained with 1 percent methylene blue to delineate the cementoenamel junction and alveolar bone crest, were obtained from a previous study that induced periodontal disease by means of ligatures in two groups of fifteen Wistar rats during 9 weeks. Ligatures were placed around the right upper second molars, and the contra-lateral teeth remained as intra-group controls. Digital photographs were taken from the specimens and submitted to a single, calibrated, blind examiner who performed the morphometrical evaluation of alveolar bone loss using both linear and area methods. Mean values of linear and area measurements were obtained from each side - buccal and palatal - of the specimens. The degree of association between the two methods was determined by Pearson's Correlation Coefficient. An almost perfect association (0.98) was determined between the linear and area evaluations. A mathematical formula was subsequently created to estimate the total area of alveolar bone loss, from linear mean measurements. Both methods were suitable for detecting bone level alterations. The results of the present study allow for the transformation of data and better compilation of results from different studies.

Evaluation of subcutaneous and alveolar implantation surgical sites in the study of the biological properties of root-end filling endodontic materials

OBJECTIVE: The aim of this study was to compare two methodologies used in the evaluation of tissue response to root-end filling materials in rats. MATERIAL AND METHODS: Forty rats were divided into 4 groups: in Groups I and II (control groups), empty polyethylene tubes were implanted in the extraction site and in the subcutaneous tissue, respectively; in Groups III and IV, polyethylene tubes filled with ProRoot MTA were implanted in the extraction site and in the subcutaneous tissue, respectively. The animals were killed 7 and 30 days after tube implantation, and the hemi-maxillas and the capsular subcutaneous tissue, both with the tubes, were removed. Specimens were processed and evaluated histomorphologicaly under light microscopy. The scores obtained were analyzed statistically by the Kruskal-Wallis test (p<0.05). RESULTS: There were no statistically significant differences between the implantation methods (p=0.78033, p=0.72039). It was observed that the 30-day groups presented a more mature healing process due to smaller number of inflammatory cells. CONCLUSIONS: The present study showed no differences in tissue responses as far as the implantation site and the studied period were concerned. Alveolar socket implantation methodology represents an interesting method in the study of the biological properties of root-end filling endodontic materials due to the opportunity to evaluate bone tissue response.

Effects of platelet-rich plasma on healing of alveolar socket: Split-mouth histological and histometric evaluation in Cebus apella monkeys.

Context: The prediction of implant treatment is directly influenced by the quality of the remaining bone after tooth extraction. Aims : The purpose of this experimental study was to, histologically and histometrically, evaluate the bone repair process in the central areas of extraction sockets filled with platelet-rich plasma. Materials and Methods: Four young adult male Cebus apella monkeys were used. The extraction of both right and left inferior second premolars was accomplished. After extraction, in one of the extraction sockets, coagulum was maintained while in the other it was removed; the alveolus was dried with gauze compress and filled up with platelet concentrate. For PRP production, Sonnleitner's protocol was followed. The specimens for histological and histometric assessment were obtained in 30, 90, 120 and 180 days intervals. Results: In 30 days new bone formation was intense in both experimental and control sockets and no significant differences were observed between the two groups. After 90 days of the extraction, while the control group showed signs of decrease in osteogenesis, in the experimental unit, the process of bone formation and fibroblast-like cell proliferation remained intense. After 120 days, the PRP treated socket was occupied by large trabeculae of bone. After 180 days, the control unit was occupied mostly with bone marrow. The experimental unit remained occupied with large amounts of bone tissue. Conclusions: It was possible to conclude that bone repair was enhanced by the use of platelet- rich plasma in alveolar sockets.

Immediate implants placed into infected sockets: a case report with 3-year follow-up

The esthetics and functional integrity of the periodontal tissue may be compromised by dental loss. Immediate implants became a viable option to maintain the periodontal architecture because of their anatomic compatibility with the dental socket and the possibility of eliminating local contamination. This article describes the procedure of immediate implant placement in the anterior maxilla replacing teeth with chronic periapical lesions, which were condemned due to endodontic lesions persisting after failed endodontic treatment and endodontic surgery, and discusses the relationship between the procedure and periapical lesions. Surgical removal of hopeless teeth 11, 12 and 21 was performed conservatively in such a way to preserve the anatomy and gingival esthetics. A second surgical access was gained at the apical level, allowing the debridement of the surgical chamber for elimination of the periapical lesion, visual orientation for setting of the implants and filling of the surgical chamber with xenogenous bovine bone graft. After this procedure, the bone chamber was covered with an absorbent membrane and the healing screws were positioned on the implants. Later, a provisional partial removable denture was installed and the implants were inserted after 6 months. After 3 years of rehabilitation, the implants present satisfactory functional and esthetic conditions, suggesting that immediate implant placement combined with guided bone regeneration may be indicated for replacing teeth lost due to chronic periapical lesions with endodontic failure history in the anterior maxilla.

A integridade estética/funcional do tecido periodontal pode ser comprometida pela perda do elemento dental. Os implantes imediatos tornaram-se uma opção viável na manutenção da arquitetura periodontal, desde que haja a compatibilidade com o alvéolo e a possibilidade da contaminação local ser totalmente eliminada. O objetivo deste estudo foi descrever o procedimento de instalação de implantes imediatos na região anterior de maxila usados na reposição de dentes com lesões crônicas periapicais, discutindo a relação entre o procedimento e lesões periapicais. A remoção dos dentes condenados (11, 12 e 21) foi feita de forma conservadora a fim de preservar a estética e arquitetura periodontal. Um segundo acesso cirúrgico foi obtido a nível apical, permitindo: o debridamento da loja cirúrgica, orientação visual dos implantes e o preenchimento com enxerto ósseo bovino. A loja óssea foi coberta por uma membrana absorvível e uma prótese parcial removível provisória foi instalada e após 6 meses os implantes foram reabilitados. Após 3 anos de reabilitação, os implantes se apresentam em condições satisfatórias de estética/função, sugerindo que a instalação de implantes imediatos combinados com a regeneração tecidual guiada em lesões periapicais crônicas podem ser indicados para repor dentes perdidos devido a lesões periapicais crônicas com história de insucesso endodôntico na maxila anterior.

Diagnosis and treatment of extraction sockets in preparation for implant placement: report of three cases

This article addresses diagnostic parameters that should be assessed in the treatment of extraction sockets with dental implant placement by presenting three case reports that emphasize the relevance of the amount of remaining bone walls. Diagnosis was based on the analysis of clinical and radiographic parameters (e.g.: bone defect morphology, remaining bone volume, presence of infections on the receptor site). Case 1 presents a 5-wall defect in the maxillary right central incisor region with severe root resorption, which was treated with immediate implant placement. Cases 2 and 3 present, respectively, two- and three-wall bone defects that did not have indication for immediate implants. These cases were first submitted to a guided bone regeneration (GBR) procedure with bone graft biomaterial and membrane barriers, and the implants were installed in a second surgical procedure. The analysis of the preoperative periodontal condition of the adjacent teeth and bone defect morphology is extremely important because these factors determine the choice between immediate implant or GBR treatment followed by implant installation in a subsequent intervention.

Este artigo aborda os parâmetros clínicos que devem ser observados no diagnóstico e tratamento de alvéolos de extração por meio da instalação de implantes através da apresentação de casos clínicos, enfatizando a importância do número de paredes ósseas. O diagnóstico baseou-se na análise de parâmetros clínicos e radiográficos (p. ex: morfologia do defeito ósseo, volume ósseo remanescente, presença de infecção na área receptora). O Caso 1 apresenta um defeito de 5 paredes relacionado a um incisivo central superior direito que apresentava extensa reabsorção radicular e foi tratado através da técnica de implante imediato. Os Casos 2 e 3 consistem em defeitos de 2 e 3 paredes ósseas presentes, respectivamente, que inicialmente não devem ser tratados com implantes imediatos, e, por isso, foram submetidos inicialmente ao procedimento de regeneração óssea guiada, com uso de biomateriais para enxertia e barreiras de membrana, para receberem implantes numa segunda etapa cirúrgica. A avaliação prévia das condições periodontais dos dentes adjacentes e da morfologia do defeito ósseo são extremamente importantes, uma vez que determinam se determinada área será tratada pela técnica de ROG ou pela técnica de implantes imediatos.

Potential for osseous regeneration of platelet-rich plasma--a comparative study in mandibular third molar sockets.

Platelet-rich plasma (PRP), the concentrate of platelets in plasma contains various growth factors that enhance osseous regeneration. This study utilized homologous platelet-rich plasma in the treatment of third molar extraction sockets in a total of fourteen human subjects, who were randomly assigned into one control and one test group, each comprising of seven members. Clinical parameters like pain on palpation, number of analgesic tablets consumed, swelling, degree of mouth opening, and condition of mucosa overlying the surgical site were assessed at intervals of 1,3,5,7,9,12, and 16 weeks post operatively. The margins between the socket and surrounding bone, radiopacity of bone filling the socket, and presence oftrabecular bone formation were evaluated simultaneously. Soft tissue healing differed significantly between the two groups, with the test group exhibiting better results. Radiographic evidence of bone formation was visible as early as I week in test subjects. It was concluded that PRP contributed to better healing of soft tissues and bone and is a viable means of growth factor delivery.

Histologic study of use of microfibrillar collagen hemostat in rat dental sockets

The aim of this paper was to evaluate if the placement of microfibrillar collagen hemostat (MCH) into a dental socket interfered with healing. General anesthesia was administered to 30 adult male Albinus Wistar rats and the maxillary right central incisor was extracted. In the control group after each tooth was extracted, the socket was sutured. In the MCH group after each tooth was extracted, MCH was placed into the socket before suturing. Postoperatively, 5 animals were sacrificed from each group at 7, 21 and 28 days. The right maxilla was removed from each animal and histologic slides were stained with Masson's trichromic and hematoxylin and eosin. Quantitative and qualitative analyses were done. The percentage of bone area in the dental socket was quantified using the Image Lab 98 image analysis system. The bone area formation for the control and MCH groups was: 8.1 percent and 3.3 percent at 7 days, 34.4 percent and 33 percent at 21 days and 41 percent and 41.3 percent at 28 days, respectively. We concluded that MCH interferes with the beginning of dental socket healing but does not interfere with the final healing of the dental socket