Decoronation followed by dental implants placement: fundamentals, applications and explanations

ABSTRACT Dental arches areas with teeth presenting dentoalveolar ankylosis and replacement root resorption can be considered as presenting normal bone, in full physiological remodeling process; and osseointegrated implants can be successfully placed. Bone remodeling will promote osseointegration, regardless of presenting ankylosis and/or replacement root resorption. After 1 to 10 years, all dental tissues will have been replaced by bone. The site, angulation and ideal positioning in the space to place the implant should be dictated exclusively by the clinical convenience, associated with previous planning. One of the advantages of decoronation followed by dental implants placement in ankylosed teeth with replacement resorption is the maintenance of bone volume in the region, both vertical and horizontal. If possible, the buccal part of the root, even if thin, should be preserved in the preparation of the cavity for the implant, as this will maintain gingival tissues looking fully normal for long periods. In the selection of cases for decoronation, the absence of microbial contamination in the region - represented by chronic periapical lesions, presence of fistula, old unconsolidated root fractures and active advanced periodontal disease - is important. Such situations are contraindications to decoronation. However, the occurrence of dentoalveolar ankylosis and replacement resorption without contamination should neither change the planning for implant installation, nor the criteria for choosing the type and brand of dental implant to be used. Failure to decoronate and use dental implants has never been reported.

RESUMO Áreas dos maxilares com dentes em anquilose alveolodentária e reabsorção dentária por substituição podem ser consideradas como portadoras de osso normal, em pleno processo fisiológico contínuo de remodelação; e os implantes osseointegráveis podem ser aplicados com sucesso. A remodelação óssea promoverá sua osseointegração, independentemente de haver raízes em anquilose e/ou em reabsorção por substituição. Após 1 a 10 anos, todos os tecidos dentários terão sido substituídos por osso. O local, a angulação e o posicionamento ideal no espaço para se colocar o implante devem ser ditados pela conveniência clínica associada, exclusivamente, ao planejamento prévio. Uma das vantagens da decoronação com colocação imediata de implantes em dentes anquilosados e com reabsorção por substituição é a manutenção do volume ósseo na região, tanto vertical quanto horizontalmente. Se possível, deve-se preservar, na preparação da cavidade para o implante, a parte vestibular da raiz, mesmo que fina; isso deixará os tecidos gengivais com aspecto de plena normalidade por longos períodos. O importante na seleção de casos para a decoronação é a ausência de contaminação microbiana na região, representada por lesões periapicais crônicas, presença de fístula, fraturas radiculares antigas não consolidadas e doença periodontal avançada ativa. Essas situações são contraindicações para a decoronação. A ocorrência de anquilose alveolodentária e reabsorção por substituição sem contaminação não deve mudar o planejamento para instalação de implantes, nem mesmo os critérios de escolha do tipo e marca de implante dentário a ser utilizado. Nunca foi relatado fracasso na decoronação e uso de implantes dentários.

Stability and bone loss around submerged and non-submerged implants in diabetic and non-diabetic patients: a 7-year follow-up

Abstract To evaluate peri-implant bone loss (PIBL) and stability around submerged and non-submerged dental implants in patients with and without type 2 diabetes mellitus (T2DM). Thirty-five T2DM and non-diabetic (NT2DM) patients were included in this study. Demographic data were recorded using a questionnaire and PIBL was measured on digital radiographs. Resonance frequency analysis (RFA) was carried out for each implant at the time of fixture placement and at 3 months in both groups. P values less than 0.05 were considered statistically significant. One hundred and eighteen dental implants with a mean height of 10 to 12 mm and 3.3 to 4.1 mm in diameter were placed. The comparison of the mean RFA values at baseline and at 3 months was statistically significant (p = 0.008) in T2DM patients. The inter-group mean RFA values at baseline and at 3 months were not significant (p > 0.05). PIBL was significantly high in T2DM as compared to NT2DM patients at each follow-up (p < 0.05). At 2, 3, and 7 years, non-submerged dental implants showed significantly high PIBL in T2DM patients as compared to NT2DM individuals (p<0.05). The results of the present clinical study demonstrate increased PIBL around non-submerged single-tooth implant-supported restorations in T2DM patients, which may be due to the immune inflammatory status.

The role of potassium channels in the endothelial dysfunction induced by periodontitis

Abstract Objective: Periodontitis is associated with endothelial dysfunction, which is clinically characterized by a reduction in endothelium-dependent relaxation. However, we have previously shown that impairment in endothelium-dependent relaxation is transient. Therefore, we evaluated which mediators are involved in endothelium-dependent relaxation recovery. Material and methods: Rats were subjected to ligature-induced experimental periodontitis. Twenty-one days after the procedure, the animals were prepared for blood pressure recording, and the responses to acetylcholine or sodium nitroprusside were obtained before and 30 minutes after injection of a nitric oxide synthase inhibitor (L-NAME), cyclooxygenase inhibitor (Indomethacin, SC-550 and NS- 398), or calcium-dependent potassium channel blockers (apamin plus TRAM- 34). The maxilla and mandible were removed for bone loss analysis. Blood and gingivae were obtained for C-reactive protein (CRP) and myeloperoxidase (MPO) measurement, respectively. Results: Experimental periodontitis induces bone loss and an increase in the gingival MPO and plasmatic CRP. Periodontitis also reduced endothelium-dependent vasodilation, a hallmark of endothelial dysfunction, 14 days after the procedure. However, the response was restored at day 21. We found that endothelium-dependent vasodilation at day 21 in ligature animals was mediated, at least in part, by the activation of endothelial calcium-activated potassium channels. Conclusions: Periodontitis induces impairment in endothelial-dependent relaxation; this impairment recovers, even in the presence of periodontitis. The recovery is mediated by the activation of endothelial calcium-activated potassium channels in ligature animals. Although important for maintenance of vascular homeostasis, this effect could mask the lack of NO, which has other beneficial properties.

Comparing osteogenic effects between concentrated growth factors and the acellular dermal matrix

Abstract Concentrated growth factor (CGF) is an autogenuous product that contains highly concentrated number of platelets and can be derived from venous blood by selective centrifugation. It has been speculated that local growth factors in human platelets (insulinlike growth factor, IGF; transforming growth factor, TGF-b; platelet derived growth factor, PDGF) would enhance healing of grafts and also counteract resorption. The osteogensis effect of CGF and acellular dermal matrix (ADM) for alveolar cleft defects was evaluated in this study. Twenty alveolar cleft patients were divided randomly into two groups. One group underwent guided bone regeneration (GBR) using acellular dermal matrix film combined with alveolar bone grafting using iliac crest bone grafts (GBR group), while the other group underwent alveolar bone grafting combined with CGF (CGF group). Cone beam computed tomography (CBCT) images were obtained at 1 week and 6 months following the procedure. Using Mimics 17.0 software, the bone resorption rate and bone density improvement rate were calculated and compared between the two groups. Although not significant between ADM and CGF in bone resorption rate, the bone density improvement in cases with CGF(61.62 ± 4.728%) was much better than in cases with ADM (27.05 ± 5.607%) (p = 0.0002). Thus, CGF could be recommended to patients with alveolar cleft as a better choice.

Methodological aspects in the study of periodontal breakdown in rats: influence of the presence and time of ligature / Aspectos metodológicos no estudo da destruiçãoperiodontal em ratos: influência da presençae tempo de ligadura

The aim of the present work was to evaluate the effect of different times on alveolar bone loss (ABL) and whether the presence of ligature on one side affects ABL on the contralateral site.This is a secondary analysis of databases from studies conductedat the Federal University of Rio Grande do Sul. Included studiesused ligature­induced periodontal disease in rats. In order to beincluded, the studies were required to have a control group withoutany ligatures and an intra­group control. Three studies were included, which used different time periods: 2 weeks with ligatureand 8 weeks without ligature; 5 weeks with ligature and 17 weekswithout ligature; 22 weeks with and without ligature. Animals wereraised similarly and sacrificed by decapitation. Maxillae weredefleshed with 9% sodium hypochlorite. Pictures were taken andfive measurements were obtained from each image.The presence of ligature generated significantly greater ABL compared to sides without ligature. Comparing sides with ligature, ABL was lower at 2 weeks than at 5 and 22 weeks. Sides without ligature showed no significant difference between 8 and 17 weeks for spontaneous periodontitis. However, after22 weeks, animals exhibited significantly greater ABL whencompared to other periods. The presence of ligature on oneside did not influence ABL on the contralateral side. Two weeks of ligature­induced periodontal disease seems to besufficient to demonstrate significant ABL. Teeth withoutligature contralateral to teeth with ligature may be considered sound controls, thereby reducing the amount of animals neededin periodontal research.

Avaliar o efeito de diferentes períodos experimentais e se a presença de ligadura em um dos lados afeta a perda óssea alveolar (POA) no lado contra lateral. O presente estudo trata se de uma análise secundária dos bancos de dados de estudos realizados na Universidade Federal do Rio Grande do Sul. Os estudos incluídos utilizaram o modelo de indução de doença periodontal por ligadura em ratos. Os estudos necessitavam possuir grupo controle sem ligadura, assim como controle intra­ grupo. Foram incluídos 3 estudos, com diferentes períodos de análise: 2 semanas com ligadura e 8 semanas sem ligadura;5 semanas com ligadura e 17 semanas sem ligadura; 22semanas com e sem ligadura. Os ratos foram criados nas mesmas condições, sacrificados por decapitação, as maxilas retiradas e os tecidos moles removidos com hipoclorito de sódio 9%. Tomadas fotográficas foram realizadas e cinco mensurações foram obtidas de cada imagem. A presença de ligadura gerou uma perda óssea alveolar significativamente maior quando comparado ao lado sem ligadura. Nos lados com ligadura um período de 2 semanas mostra menor perda óssea alveolar que 5 e 22 semanas. Lados sem ligadura foram avaliados e não observou­ se diferença significativa entre 8 e 17 semanas para periodontite espontânea. No entanto a partir de 22 semanas os animais exibiram significativamente maior perda óssea alveolar quando comparado aos demais tempos experimentais. A presença de ligadura em um dos lados não influenciou a perda óssea do lado contra lateral. Duas semanas de doença periodontal induzida por ligadura parece ser suficiente para demonstrar perda óssea significativa e a utilização de lados contra laterais de dentes com ligadura é possível de ser considerada como controles saudáveis, reduzindo o número de animais em pesquisa.

Effects of Nonsurgical Periodontal Treatment on the Alveolar Bone Density

The aim of this study was to evaluate the effects of nonsurgical periodontal treatment on alveolar bone density (ABD) and bone height (BH) using direct digital radiography. Nineteen patients (mean age: 36±7.3 years) with generalized chronic periodontitis were examined at baseline, 90 (90AT) and 180 (180AT) days after nonsurgical periodontal therapy. Radiographs were taken from two sites with specific characteristics: 39 sites with probing pocket depth (PPD)≤3 mm and clinical attachment level (CAL)≤1 mm (shallow sites); and 62 sites with PPD≥5 mm and CAL≥3 mm (deep sites). The ABD was assessed considering the bone regions of interest at the alveolar bone crest (ROI I) and at the medullar bone (ROI II). The BH was assessed considering the distance from the alveolar bone crest to the cementoenamel junction. Mann-Whitney test was used for the overall demographic data, Wilcoxon test was used to compare the baseline, 90AT and 180AT data as well as to compare the groups and subgroups within the same evaluation period. The significance level was set at 5%. The deep sites showed a significant increase of ABD in ROI I at 90AT (p<0.007) and at 180AT (p<0.005). ABD decrease was seen in ROI II at 180AT (p<0.04) while BH reduced only in shallow sites at 90AT. In conclusion, an increase in ABD was observed in deep sites of patients with generalized chronic periodontitis. However, no significant change in alveolar BH was observed in these sites.

O objetivo desse estudo foi avaliar os efeitos do tratamento periodontal não cirúrgico na densidade do osso alveolar e na altura óssea alveolar usando radiografias digitais diretas. Dezenove pacientes (média de idade 36±7,3 anos) com pacientes com periodontite crônica generalizada foram examinados no tempo 0 e aos 90 (90AT) e 180 (180AT) dias após o tratamento periodontal não cirúrgico. Dois grupos de sítios foram radiografados, 39 com profundidade de bolsa a sondagem (PBS)≤3 mm e nível de inserção clínica (NIC)≤1 mm (sítios rasos) e 62 com PBS≥5 mm and NIC≥3 mm (sítios profundos). A densidade foi avaliada considerando as regiões ósseas de interesse na crista óssea alveolar (ROI I) e no osso medular (ROI II). A altura óssea compreendia a distância entre a crista óssea alveolar e a junção cemento-esmalte. Os sítios profundos mostraram um significante aumento na densidade óssea na ROI I tendo p<0,007 em 90AT e p<0,005 em 180AT. Uma redução na densidade óssea foi vista na ROI II 180AT (p<0,04) enquanto a altura óssea reduziu somente nos sítios rasos 90 AT. Como conclusão, um aumento na densidade foi observado na crista óssea alveolar de sítios profundos em pacientes com periodontite. No entanto, nenhuma alteração significante na altura óssea alveolar foi observada nesses sítios.

Effect of chronic stress in newborn rats on the progression of ligature-induced-periodontitis in adulthood

PURPOSE: To investigate the effect chronic stress in newborn rats on the progression of ligature-induced-periodontitis in adulthood. METHODS: Ten couples of adult Wistar rats were selected for mating. After birth, the female and their respective offsprings were allocated into two groups. Ligature Group (LG): offsprings were only watched during breast-feeding; Stress-ligature Group (SLG): after 24h of live birth, the offsprings were moved away from their mothers every day for four hours during breast-feeding for 20 days; in both approaches, after reaching ± 250g, ten rats were included in the groups. Periodontal disease was induced by a silk suture placed around the maxillary right second molar. The left side was used as control. After 15 days, the animals were subjected to euthanasia, maxillary bones were removed and stored in 10% formaldehyde. After 48h, radiographs were taken and revealed and were used for bone destruction analysis. Examiner was blind and calibrated for measurements. RESULTS: Stress-ligature group presented higher bone loss values in relation to ligature group (p<0.05). CONCLUSION: Exposure to chronic stress imposed on offsprings produced a greater progression of bone loss induced during adulthood.

Atrofia paraprotética de los maxilares / Paraprosthetic atrophy of the jaws

El objetivo de esta presentación es describir las alteraciones provocadas por la desadaptación o sobrecarga sectorizada de las prótesis mucosoportadas sobre el terreno de soporte óseo. Luego, relacionarlas con las alteraciones periprotéticas asociadas más comunes, y realizar la descripción de una de las alteraciones atróficas paraprotéticas de mayor casuística, con sus consecuencias en el sistema estomatognático. Finalmente, describir los tratamientos protéticos no implantológicos y la prevención de estas alteraciones con prótesis convencionales e implanto-asistidas

Análise da presença de citocinas no periodonto de ratos diabéticos tratados com chá verde / Cytokines expression analyses in periodontium of diabetic rats treated with green tea

As doenças periodontais (DPs) são alterações inflamatórias crônicas que acometem os tecidos de sustentação do órgão dental. A presença do diabetes é refletida em maior severidade e prevalência das DPs tanto em humanos quanto em modelos experimentais. Contudo, os mecanismos biológicos envolvidos no aumento da prevalência e da severidade permanecem pouco conhecidos. Desta forma, o objetivo deste estudo foi avaliar o número de células marcadas por imunohistoquímica para TNF-α, RANKL, OPG, IL-10 e para o fator de transcrição RUNX-2, na doença periodontal experimental decorrente da indução do diabetes em ratos. Além disso, avaliamos os possíveis efeitos do tratamento com chá verde sobre o periodonto dos animais. Inicialmente, os ratos (n=80) foram submetidos à indução do diabetes por administração intraperitoneal de estreptozotocina (50mg/kg) e, juntamente com o grupo controle (n=40), foram subdivididos em animais tratados com chá verde ou com água, acompanhados durante o período de 15, 30, 60 ou 90 dias. Após o sacrifício dentro do tempo determinado para cada grupo, as hemimaxilas coletadas passaram pelos procedimentos de imunohistoquímica. Os resultados revelaram que a presença do diabetes causou perda óssea alveolar, compatível com o desenvolvimento da doença periodontal e resultou em alterações significativas no número de células imunomarcadas para diferentes mediadores do processo inflamatório. Entretanto, o chá verde apresentou efeitos benéficos para o periodonto, alterando a marcação das citocinas envolvidas. Nos animais diabéticos, independente do tratamento, foi observado aumento estatisticamente significativo (p<0,05 ANOVA) no número de células imunomarcadas para TNF-α e RANKL. Inversamente, houve menor marcação para OPG (60 e 90 dias), RUNX-2 (30, 60 e 90 dias) e para IL-10 (30, 60 e 90 dias) nos animais que ingeriram água. Porém, os diabéticos tratados com chá não demonstraram diferenças significativas em relação ao seu respectivo controle...

Periodontal diseases (PD) are chronic inflammatory diseases leading the destruction of connective tissue and alveolar bone supporting the teeth. The establishment of diabetes increases PD prevalence and severity in humans and experimental model. However, biological mechanisms regarding to increase of prevalence and severity remains poorly known. The aim of this study was to evaluate the number of immuno-staining cells to TNF-α, RANKL, OPG, IL-10 and transcription factor RUNX-2 in experimental periodontal disease in diabetic rats. Furthermore, the possible green tea efects were evaluated in periodontiumof the rats. Diabetes was induced in Wistar rats (n=120) by intraperitoneal administration of 50 mg/kg ofstreptozotocin and together with control animals (n=80), the rats were subdivided in water or green tea treated group, that were analyzed at 15, 30, 60 and 90 days after diabetes induction. The animals were sacrificed and the hemimaxillae were removed and submitted to immunohistochemistry procedures. Our data demonstrated that diabetes induction and progression resulted in significant bone loss and alterations in number of immuno-staining cells to different mediators of inflammatory process. However, the green tea showed positive effects in periodontium through inflammation modulation. In diabetic rats, regardless of treatment, we observed an increased number of immuno-staining cells to TNF-α, IL-1b and RANKL (p<0,05 ANOVA). On the other hand, in water treated diabetic rats, there were a decreased number of immuno-staining cells to OPG (60 e 90 days), RUNX-2 (30, 60 e 90 days) and IL-10 (30, 60 e 90 days). However, the green tea treated rats did not showed statistical differences between control and experimental groups in those staining. When we compared both diabetic groups, green tea and water treated, the animals that drank the green tea showed decreased number of immuno-staining cells to TNF-α and RANKL(p<0,05 ANOVA) whereas the number...

Papillon-Lefevre syndrome: a case report.

Papillon-Lefevre syndrome is a rare autosomal recessive genetic disorder. The clinical manifestations include palmer planter hyperkeratosis with precocious progressive periodontal disease that results in premature exfoliation of primary and permanent dentitions. Patients are often edentulous at an early age. This is a case report of prosthodontic rehabilitation of a 15-year-old girl with Papillon-Lefevre syndrome.

Factor de necrosis tumoral Alfa (TNF-alfa) / Alpha tumor necrosis factor (TNF-alpha)

Esta revisión presenta el conocimiento reciente sobre el factor de necrosis tumoral alfa (TNF-alfa), en especial los mecanismos de liberación desde macrófagos y su relación con enfermedades inflamatorias y estrés oxidativo. En odontología, TNF-alfa se relaciona con rápida pérdida de hueso alveolar en enfermedad periodontal. La inducción de apoptosis es otro de sus interesantes efectos

Colocación de un implante único en un paciente diabético tipo II: presentación de un caso / Placement of a single implant in a type II diabetic patient: report of a case

Esta presentación de caso sugiere que pacientes con diabetes tipo II pueden ser considerados para una terapia con implantes dentales, siempre y cuando los controles de higiene bucal y el estado de su glucemia fueran correctos. Se colocó un implante en un paciente de 52 años con diabetes tipo II. A los siete meses de ser colocado el implante y ser cargado, los resultados presentaron un pronóstico favorable, ya que los parámetros de higiene bucal y glucemia mostraban resultados alentadores. El paciente siguió siendo controlado una vez por mes, luego de esta fecha. Los resultados siguieron siendo positivos. Al año de colocado el implante, los controles se fueron espaciando por ausencia del paciente. A los 16 meses el paciente vino a la consulta. El implante tenía movilidad y en la radiografía aparecieron muestras de reabsorción. Los valores de glucemia (301 mg/dl) dieron valores muy altos y con presencia de glucosa en orina, siendo sumamente peligrosos para la estabilidad del implante y para la salud de los pacientes

La osteoporosis: sus efectos sobre la cavidad bucal / Osteoporosis: their effects on the oral cavity

La osteoporosis es una enfermedad compleja y multifactorial, originada por un desorden en el metabolismo óseo esquelético, lo cual se traduce en una reducción en la cantidad de hueso, sin producir variaciones en la composición química del mismo. Es importante establecer el término de Osteoporosis en Odontología. Se ha determinado la importancia de esta enfermedad y su relación con los huesos maxilares. Esta patología ha sido demostrada en diversos sitios del esqueleto, especialmente en aquellos huesos con gran proporción de tejido trabecular, como es el caso de la mandíbula; la pérdida de substancia ósea en los maxilares constituye un signo que advierte la existencia de enfermedades óseas sistémicas en humanos. Los cambios en la anatomía de la mandíbula son de gran interés odontológico, ya que la disminución progresiva de substancia ósea mandibular reduce la posibilidad de una efectiva rehabilitación de la función bucal, lo cual debe considerarse durante la planificación del tratamiento odontológico

Movilidad dentaria: su importancia clínica / Tooth mobility: its clinical relevance

Las estructuras de soporte del diente responden mediante diversos mecanismos adaptativos a la fuerza que recibe el diente. Así, ante una fueza axial unidireccional, el dinte cambia de posición y los tejidos vuelven luego a la normalidad, ante una fuerza de vaivén los cambios dar n como resultado final un aumento del ancho del ligamento periodontal y un aumento de la movilidad progresiva ("adaptación"). Cuando la acción de las fuerzas se combina con la enfermedad periodontal inflamatoria activa, puede ocurrir que si queda poco tejido de inserción el ligamento periodontal no pueda adaptarse a las fuerzas oclusales y aparecer entonces una movilidad progresiva que puede determinar la pérdida del diente

Reconstrucción alveolar primaria con microfijación y colocación de implantes / Primary alveolar reconstruction with microfixation and implants placement

Proponemos esta técnica de regeneración alveolar para el sector anterior, específicamente para la zona del primer premolar a primer premolar en maxilar superior, sobre todo cuando el hueso en esa zona no es lo suficientemente ancho. Se realiza la disyunción del reborde alveolar y a continuación colocamos implantes cilíndricos roscados. LUego fijamos la tabla vestibular con placa de titanio y microtornillos

Movilidad dentaria: su importancia clínica / Tooth mobility: its clinical relevance

Las estructuras de soporte del diente responden mediante diversos mecanismos adaptativos a la fuerza que recibe el diente. Así, ante una fuerza axial unidireccional, el diente cambia de posición y los tejidos vuelven luego a la normalidad; ante una fuerza de vaivén, los cambios darán como resultado final un aumento del ancho del ligamento periodontal y un aumento de la movilidad no progresiva ("adaptación"). Cuando la acción de las fuerzas se combina con la enfermedad periodontal inflamatoria activa, puede ocurrir que si queda poco tejido de inserción, el ligamento periodontal no pueda adaptarse a las fuerzas oclusales y aparecer entonces una movilidad progresiva que puede determinar la pérdida del diente

Periodontitis del fumador / Smoker's periodontitis

El efecto del hábito de fumar en pacientes con patologías gingivoperiodontales, ha sido seriamente estudiada en los últimos años. A pesar de que la placa bacteriana no difiere en el fumador resoecto del no fumador hay, en cambio, efectos perjudiciales en los mecanismos defensores de la encía, cemento radicular, formación de cálculos, etc. Estas evidencias determinan una terapia con algunas diferencias en relación al tratamiento habitual y un riesgo de recidiva de la lesión más pronunciado que en un paciente no fumador