Effects of oestrogen deficiency and 17ß-estradiol therapy on bone healing in calvarial critical size defects treated with bovine bone graft.

OBJECTIVE: To histomorphometrically analyze the effect of ovariectomy-induced oestrogen deficiency and 17ß-estradiol therapy on bone healing of surgically created critical-size defects (CSDs) treated with bovine bone graft (BBG). METHODS: Forty-eight female rats were randomly assigned to the following 3 experimental groups (n=16): sham-operated animals (SHAM), ovariectomized animals (OVX) and ovariectomized animals treated with oestrogen (OVX+E2). OVX+E2 animals received daily subcutaneous injections of 17ß-estradiol (20µg/kg) from 8 days after ovariectomy until euthanasia. Thirty days after the surgery, an 8mm CSD was surgically created in each calvaria of all animals and filled with BBG. Animals were euthanized at either 30 or 60 days postoperative. A histological analysis, percentage of Newly Formed Bone Area (NFBA), osteoblast and osteoclast number was histomorphometrically performed (p≤0.05). RESULTS: At 30 days, SHAM group (8.82%±2.93) had significantly greater NFBA than OVX (4.66%±1.35) and OVX+E2 groups (5.85%±4.08) (p≤0.05). At 60 days, SHAM group (11.51%±3.08) and OVX+E2 group (9.84%±1.87) had significantly greater NFBA than OVX animals (5.12%±0.68) (p≤0.05). Fewer osteoblasts were observed in the OVX group at 30 (763.40±121.60) and 60 (696.60±80.92) days than in the SHAM group at 30 days (1356.00±95.38). Fewer osteoclasts were observed in the OVX+E2 group (3.25±2.16) than in the SHAM (9.75±1.82) and OVX (12.75±1.47) groups at 30 days (p≤0.05). CONCLUSIONS: Oestrogen deficiency compromises bone healing in calvarial CSDs treated with BBG in ovariectomized rats. After 60 days post-surgery, 17ß-estradiol therapy improved bone healing in calvarial CSDs treated with BBG in ovariectomized rats.

Evaluation of collagen-based membranes for guided bone regeneration, by three-dimensional computerized microtomography.

OBJECTIVE: The aim of this study was to evaluate the use of a collagen-based membrane compared with no treatment on guided bone regeneration by 3-dimensional computerized microtomography (µCT). STUDY DESIGN: Defects were created between the mesial and distal premolar roots of the second and third premolars (beagle dogs; n = 8). A collagen-based membrane (Vitala; Osteogenics Biomedical Inc., TX, USA) was placed in one of the defects (membrane group; n = 16), and the other was left untreated (no-membrane group; n = 16). Left and right sides provided healing samples for 2 and 16 weeks. Three-dimensional bone architecture was acquired by µCT and categorized as fully regenerated (F, bone height and width) or nonregenerated (N). RESULTS: Chi-square tests (95% level of significance) showed that tooth did not have an effect on outcome (P = .5). Significantly higher F outcomes were observed at 16 weeks than 2 weeks (P = .008) and in membrane group than in no-membrane group (P = .008). CONCLUSIONS: The collagen-based membrane influenced bone regeneration at the furcation.

Nicotine-induced damage affects gingival fibroblasts in the gingival tissue of rats.

BACKGROUND: Very limited information is available from in vivo studies about whether smoking and/or nicotine affect gingival tissues in the absence of plaque. The purpose of this study is to evaluate the effect of the systemic administration of nicotine in the proliferation and counting of fibroblast-like cells in the gingival tissue of rats. METHODS: Thirty adult male Wistar rats were randomly assigned into two groups to receive subcutaneous injections of a saline solution (control group = group C) or nicotine solution (group N; 3 mg/kg) twice a day. The animals were euthanized 37, 44, or 51 days after the first subcutaneous injection. Specimens were routinely processed for serial histologic sections. Five fields of view in the connective tissue adjacent to the gingival epithelium and above the alveolar bone crest of the maxillary first molar were selected for the counting of fibroblast-like cells. Data were statistically analyzed (P <0.05). RESULTS: The intergroup analysis detected a lower number of fibroblast-like cells in group N compared to group C on days 37 (2.65 ± 1.41 and 6.67 ± 3.25, respectively), 44 (2.70 ± 1.84 and 8.57 ± 2.37, respectively), and 51 (2.09 ± 1.41 and 7.49 ± 2.60, respectively) (P <0.05). The quantification of fibroblast-like cells showed no significant difference (P >0.05) in the intragroup analysis of control and nicotine throughout experimental periods. In the intergroup analysis, group N had reduced proliferating cell nuclear antigen-positive fibroblasts compared to group C in all periods (P <0.05). CONCLUSION: The daily systemic administration of nicotine negatively affected, in vivo, the number and proliferation of fibroblast-like cells in the gingival tissue of rats.

Treatment of experimental periodontal disease by photodynamic therapy in rats with diabetes.

BACKGROUND: The aim of this study was to evaluate histologically and histometrically the influence of photodynamic therapy (PDT) as an adjuvant treatment on induced periodontitis in rats with diabetes. METHODS: Two hundred forty rats were divided evenly into two groups: non-diabetic (ND; n = 120) and alloxan diabetic (D; n = 120). Periodontal disease was induced in both groups at the first mandibular molar. After 7 days, the ligature was removed, and all animals underwent scaling and root planing (SRP) and were divided according to the following treatments: irrigation with saline solution (SRP); irrigation with a phenothiazinium dye (100 microg/ml) (TBO); laser irradiation (660 nm, 24 J) (LLLT); and PDT (TBO and laser irradiation). Ten animals in each experimental group and treatment subgroup were euthanized at 7, 15, and 30 days. The histometric values were analyzed statistically (P <0.05). RESULTS: In the ND group, the animals treated by PDT showed less bone loss (0.33 +/- 0.05 mm(2), 0.35 +/- 0.06 mm(2), and 0.27 +/- 0.07 mm(2) at 7, 15, and 30 days, respectively; P <0.05) at all experimental periods than the SRP group (1.11 +/- 0.11 mm(2), 0.84 +/- 0.12 mm(2), and 0.97 +/- 0.13 mm(2) at 7, 15, and 30 days, respectively), the TBO group (0.51 +/- 0.12 mm(2), 0.70 +/- 0.13 mm(2), and 0.64 +/- 0.08 mm(2) at 7, 15, and 30 days, respectively), and the LLLT group (0.59 +/- 0.03 mm(2), 0.61 +/- 0.04 mm(2), and 0.60 +/- 0.03 mm(2) at 7, 15, and 30 days, respectively). In the D group, the animals treated by PDT showed less bone loss (0.29 +/- 0.03 mm(2), 0.24 +/- 0.02 mm(2), and 0.27 +/- 0.06 mm(2) at 7, 15, and 30 days, respectively; P <0.05) at all experimental periods than the SRP group (2.27 +/- 0.47 mm(2), 3.23 +/- 0.34 mm(2), and 2.82 +/- 0.75 mm(2) at 7, 15, and 30 days, respectively), the TBO group (0.51 +/- 0.15 mm(2), 0.44 +/- 0.07 mm(2), and 0.57 +/- 0.13 mm(2) at 7, 15, and 30 days, respectively), and the LLLT group (0.37 +/- 0.05 mm(2), 0.35 +/- 0.09 mm(2), and 0.39 +/- 0.12 mm(2) at 7, 15, and 30 days, respectively). CONCLUSION: PDT was a beneficial adjuvant treatment for periodontal diseases induced by bacterial plaque and systemically modified by diabetes mellitus.

Influence of nicotine on healing process of autogenous bone block grafts in the mandible: a histomorphometric study in rats.

PURPOSE: The aim of this study was to perform qualitative and quantitative analyses of the effect of nicotine on autogenous bone block grafts and to describe events in the initial healing phase and the differences in the repair processes between animals exposed to nicotine and controls. MATERIALS AND METHODS: Forty-eight female Wistar rats were randomly divided into 2 groups, the nicotine group and the saline group. All animals received either nicotine (3 mg/kg) or saline 4 weeks before the surgical procedure and continued to receive nicotine from surgery to sacrifice at 7, 14, or 28 days. The autogenous bone block graft was harvested from the calvaria and stabilized on the external cortical area near the angle of the mandible. RESULTS: The histologic analyses of the nicotine group depicted a delay in osteogenic activity at the bed-graft interface, as well as impairment of the organization of the granulation tissue that developed instead of blood clot. Nicotine-group specimens exhibited less bone neoformation, and the newly formed bone was poorly cellularized and vascularized. The histometric analysis revealed significantly less bone formation in the nicotine group at both 14 days (23.75% +/- 6.18% versus 51.31% +/- 8.31%) and 28 days (42.44% +/- 8.70% versus 73.00% +/- 4.99%). CONCLUSION: Nicotine did jeopardize the early healing process of autogenous bone block grafts in rats but did not prevent it.

Influence of ovariectomy on healing of autogenous bone block grafts in the mandible: a histomorphometric study in an aged rat model.

PURPOSE: The aim of this study was to evaluate quantitatively and qualitatively the influence of estrogen deficiency on autogenous bone block grafts in aged ovariectomized rats. MATERIALS AND METHODS: Fifty 12-month-old female Wistar rats were used in the study. They were divided into 2 groups, an ovariectomized group and a sham-operated group. After 30 days the animals received autogenous block bone grafts on the angle of the mandible, harvested from the calvaria. The animals were euthanized at 7, 14, or 28 days postoperatively. RESULTS: Histologic analysis showed that at 7 days postsurgery, the interface between graft and recipient site in the sham-operated group appeared filled by a granulation tissue with angiogenic activity, whereas the ovariectomized group still exhibited a blood clot and a granulation tissue in organization. On the 14th postoperative day, the interface in the sham-operated group was partially filled by newly formed bone establishing a union between the graft and the recipient site. The interface in the ovariectomized group was typically filled by granulation tissue with discrete osteogenic activity in most specimens. On the 28th postoperative day, the graft in the sham-operated group appeared histologically integrated to the mandible. However, the interface in the ovariectomized group appeared partially filled by newly formed bone, with areas of interposed connective tissue. The statistical analysis revealed that bone neoformation was significantly greater in the sham-operated group (57.41% at 14 days and 68.35 at 28 days) in comparison with the ovariectomized group (40.82% at 14 days and 53.09 at 28 days) at the 5% level. CONCLUSION: The estrogen depletion caused by the ovariectomy hindered the healing process of autogenous block bone grafts placed in the mandibles of aged rats.

Padrão de cicatrização de defeitos de deiscência periodontal tratados com enxerto de tecido conjuntivo subepitelial ou matriz dérmica acelular: estudo histológico e histométrico em cães / Healing pattern of periodontal dehiscence defects treated with subepithelial connective tissue graft or acellular dermal matrix: histologic and histometric study in dogs

O objetivo do presente estudo foi avaliar histológica e histometricamente o padrão de cicatrização de defeitos de deiscência periodontal tratados com enxerto de tecido conjuntivo subepitelial (ETC) ou matriz dérmica acelular (MDA), cada qual comparado ao tratamento com Retalho Posicionado Coronal (RPC). Foram utilizados 10 cães, divididos em dois grupo de 5. Defeitos de deiscência óssea (6x8 mm) foram criados nos caninos superiores e os grupos divididos seguindo um modelo de boca dividida de acordo com o tratamento. Em um grupo de 5 cães foi realizado o tratamento com ETC e no lado contralateral RPC e o outro grupo de 5 cães foi tratado com MDA e RPC no lado contralateral. Após 3 meses pós-operatórios os animais foram submetidos à eutanásia e os blocos processados para análise histológica e histométrica. Os parâmetros histométricos avaliados incluíram extensão de tecido epitelial (TE), nova inserção (NITC) e aposição de tecido conjuntivo (ATC), novo cemento (NC) e novo osso (NO). Os dados histométricos transformados em porcentagem, foram estatisticamente analisados pelo teste ANOVA, seguido pelo teste de Tukey (p<0,05). Ausência de diferença estatística foi na extensão de: TE com 45,92 ± 17 para ECT e 46,70 ± 20 para RRC (P=0,9486) e de 27,58 ± 9 para MDA e 35,06 ± 24 para RPC (P=0,5519); NC foi 55,06 ± 26 para ECT e de 49,28 ± 16 para RPC (P=0,6923) e de 69,14 ± 21 para MDA e 61.59 ± 29 para RPC (P=0,6550); NO foi 18,52 ± 20 para ETC e de 16.62 ± 14 para RPC (P=0,8648) e de 27,76 ± 22 para MDA e 45,56 ± 23 para RPC (P=0,2589); NITC foi de 48,36 ± 14 para ETC e de 47,12 ± 16 para RPC (P=0,8993) e de 52,20 ± 17 para MDA e de 59,13 ± 30 (P=0,6751); ATC foi de 16,92 ± 20,45 para ETC e de 7,40 ± 4,47 para RPC (P=0,0406*) e de 27,34 ± 31 para MDA e de 13,34 ± 12,55 para RPC (P=0,6084). Diferença significativamente maior foi encontrada somente para ATC para o grupo ETC quando comparado ao RPC. Dentro dos limites do presente estudo, pode se concluir que as ...

Avaliação radiográfica do comportamento do tecido ósseo alveolar após procedimento de indução de doença periodontal em ratos / Radiographic evaluation of the alveolar bone tissue after induction of periodontal disease in rats

O presente estudo teve por objetivo avaliar radiograficamente, os efeitos provenientes da adaptação da ligadura durante a indução da doença periodontal em ratos. Para este estudo foram usados 30 ratos. No primeiro molar inferior foi adaptada uma ligadura a qual foi distribuída de forma randômica, entre o lado direito e esquerdo. O lado sem ligadura foi utilizado como controle (negativo). Logo após a adaptação da ligadura, esta foi removida. Os animais foram sacrificados no período de 0, 3 e 7 dias, tendo dez animais por período. Desta forma as mandíbulas foram removidas, separadas e fixadas em formol. As hemimandíbulas foram radiografadas e analisadas pelo sistema de imagem digital Digora, onde à distância da união cemento-esmalte à crista óssea alveolar foi mensurada em mm por um traçado linear. Os dados coletados não indicaram diferença estatisticamente significante entre os grupos e períodos experimentais analisados pelo teste T de student (p>0,05). Dentro dos limites deste estudo e da metodologia utilizada podemos concluir que a ligadura não traumatiza os tecidos periodontais e por si só não leva ao desenvolvimento da doença periodontal em ratos.

A histologic and histometric assessment of the influence of nicotine on alveolar bone loss in rats.

BACKGROUND: Cigarette smoking has long been recognized as a risk factor for periodontal disease. The aim of this study was to perform quantitative and qualitative analyses of bone loss in the furcation region of periodontally healthy rats after daily systemic administration of nicotine or saline solution. METHODS: Thirty adult male Wistar rats were assigned randomly to twice daily subcutaneous injections of saline solution (control, group C) or nicotine (group N). The animals were sacrificed at 37, 44, or 51 days after the first subcutaneous injection. The specimens were processed for serial histologic sections, and the area of bone loss in the furcation region of the second molar was analyzed histometrically. RESULTS: Greater bone loss was detected in group N compared to group C on day 37 (16.36 +/- 5.84 mm(2) and 7.24 +/- 2.66 mm(2)), day 44 (15.12 +/- 4.57 mm(2) and 7.76 +/- 1.35 mm(2)), and day 51 (18.80 +/- 3.71 mm(2) and 8.74 +/- 2.61 mm(2)), respectively (P <0.05). Extension of bone loss appeared greater in the furcation region of group N where a thinner trabeculae bone was found. After day 37, bone loss did not increase significantly. CONCLUSIONS: Daily systemic administration of nicotine resulted in significantly greater bone loss in the furcation region compared to saline solution. This indicated a close association between nicotine and periodontal morbidity in rats.

Estudo radiográfico da perda óssea alveolar em ratos tratados pela terapia fotodinâmica / Radiographic Study of the alveolar boné loss in rats treated by photodynamic therapy

O objetivo do presente estudo foi avaliar do ponto de vista radiográflco, o efeito da terapia fotodinâmica na evolução da doença periodontal induzida em ratos. A doença periodontal foi induzida através da instalação de ligaduras no primeiro molar inferior de 120 ratos, com aproximadamente 180 g., divididos em quatro grupos que receberam o seguinte tratamento: Grupo l - os ratos não receberam nenhum tratamento, apenas a presença da ligadura; Grupo 2 - foram tratados com droga fotossensibilizadora (azul de metileno); Grupo 3 - receberam tratamento com laser em baixa intensidade (LLLT) e o Grupo 4 - foram tratados com droga fotossensibilizadora e LLLT. Nos grupos 3 e 4, após dois dias da indução da doença periodontal, utilizou-se na porção mesial do primeiro molar o laser de AsGaAI (685nm) em modo contato, pontual por 120 segundos com fluência de energia de 4,5 J/cm2. Após cinco, 15 e 30 dias após indução, os animais foram sacrificados e as mandíbulas coletadas para análise radiográfica da perda óssea alveolar, na região mesial dos primeiros molares.As mandíbulas foram radiografadas, digitalizadas e analisadas por um software de análise de imagens. A análise radiográfica mostrou diferença estatisticamente significante no grupo 4 quando comparado com o grupo 1, com menor perda óssea alveolar no grupo 4, nos períodos de cinco e 15 dias pós-operatórios. No período de 30 dias não ocorreu diferença significativa entre os grupos analisados. Frente aos resultados obtidos e de acordo com a metodologia empregada, concluiu-se que a terapia fotodinâmica promoveu uma evolução diferenciada da perda óssea em ratos, principalmente nos períodos iniciais, podendo esta terapia ser uma nova opção terapêutica complementar para tratamento da doença periodontal

Lesões de bifurcação em molares inferiores induzidas endodonticamente / Bifurcation lesions in inferior molars endodontically induced

A perda de inserção periodontal é observada com freqüência na clínica odontológica. A imensa maioria dessas perdas tem origem no sulco gengival induzida pela placa bacteriana, pela cárie, com conseqüente colapso da polpa dental, ou por ambos. O objetivo do clínico é restabelecer as condições periodontais existentes antes da instalação do processo mórbido que determinou a degradação periodontal localizada. Para tanto, um diagnóstico preciso dessas lesões é fundamental para se estabelecer o prognóstico e o tratamento a ser realizado. O presente artigo demonstra, através de casos clínicos, algumas situações freqüentes onde lesões em molares inferiores com substancial destruição periodontal na região de bifurcação, oriundas exclusivamente da contaminação pulpar, tratadas endodonticamente por métodos convencionais com a utilização de trocas de curativo de hidróxido de cálcio, tiveram a total regeneração do periodonto.

Periodontal plastic surgery associated with treatment for the removal of gingival overgrowth.

BACKGROUND: Excisional biopsies of gingival overgrowths, performed with safety margins, frequently result in mucogingival defects. These defects may produce esthetic problems and increase the chances of dentin hyperesthesia and its possibility of hindering oral hygiene. METHODS: Two clinical cases are reported in which gingival overgrowths were removed by excisional biopsy, resulting in unsightly defects. The first clinical case presents an invasive approach for the treatment of a recurrent pyogenic granuloma in the anterior maxilla, and the second depicts a complete removal of a peripheral odontogenic fibroma in the posterior maxilla. In both situations, the soft-tissue defects were repaired by periodontal plastic surgery, including a laterally positioned flap and a coronally positioned flap, respectively. RESULTS: Periodontal plastic surgery successfully restored the defects that resulted from biopsies, and no recurrence has been noticed in the 5-year postoperative follow-up period. CONCLUSIONS: The combination of biopsy and periodontal plastic surgery in a one-step procedure seems to be suitable to remove gingival overgrowths in most areas of the mouth, regardless of esthetic significance. Such procedures seem to restore gingival health, encourage healing, and create both esthetics and function in the excised area.

A influência da osteoporose na implantodontia / The influence of osteoporosis on implantology

A osteoporose é definida como uma desordem esquelética sistêmica caracterizada por perda de massa óssea e deterioração da microarquitetura do tecido ósseo, propiciando um aumento da fragilidade óssea e a susceptibilidade à fratura. Neste trabalho será feita uma revisão de literatura sobre a relação existente entre a osteoporose e a implantodontia, abordando o papel do estrógeno na remodelação óssea com enfoque no processo de osseointegração. Esse tema tem despertado interesse no âmbito odontológico, uma vez que qualquer pertubação na relação celular equilibrada de neoformação e reabsorção poderiam alterar a quantidade e/ou qualidade do osso formado em torno da superfície do implante, prejudicando a osseointegração. Muitos pesquisadores têm estudado a relação entre osteoporose e a diminuição da massa óssea dos maxilares, com o intuito de avaliar o risco que a osteoporose oferece à implantodontia. No entanto, ainda existem controvérsias a respeito do risco de falhas de implantes osseointegrados em mulheres pós-menopausa com osteoporose e sobre a contra-indicação absoluta da instalação destes implantes osseointegrados, nesta condição. Com base na literatura revisada, é coerente concluir que a osteoporose não representa um fator de risco na implantodontia, desde que haja quantidade óssea suficiente na região receptora