Analysis In Vivo of Bone Modulation in Hydrophilic and Hydrophobic Titanium Implant Surfaces.

PURPOSE: To evaluate whether a hydrophilic surface treatment compared with a hydrophobic implant surface can enhance osseointegration by analysis of calcium deposition, bone-to-implant contact (BIC), bone volume (BV), and upregulation of genes involved in bone formation. MATERIALS AND METHODS: Sixty implants (n = 60) with a hydrophobic (SAE) or hydrophilic (SAE-HD) surface treatment were placed bilaterally in each femur of 3-month-old male mice (n = 30). Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) were utilized for quantifying the presence of calcium on the implant surface 7 days after implant placement. The specimens were analyzed after 14 and 21 days for BIC and BV by Nano CT scanning followed by histologic evaluation. Additionally, 1, 3, and 7 days postsurgery, femurs were harvested, implants were explanted, and gene expression (Sp7, Bsp, Sost, IL-1α, and IL-10) by quantitative real-time polymerase chain reaction was studied. Moreover, implants were characterized for surface roughness area. Data were statistically analyzed with two-way analysis of variance (ANOVA) followed by the Tukey test (P < .05). RESULTS: The amount of calcium on the surface was higher for SAE-HD after 7 days. Nano CT revealed significantly more BV in the SAE-HD than the SAE surface. The histologic assessment showed increased BIC in SAE-HD in comparison to SAE. SAEHD showed significantly increased levels of genes involved in bone formation. CONCLUSION: Both surfaces were able to modulate bone responses toward osteoblast differentiation. SAE-HD presented a better response compared with SAE.

Hydrophilic titanium surface modulates early stages of osseointegration in osteoporosis.

OBJECTIVE: Using a mouse osteoporotic model, this study aimed to determine the influence of hydrophilic titanium surfaces on gene expression and bone formation during the osseointegration process. BACKGROUND: Based on the previous evidence, it is plausible to assume that osteoporotic bone has a different potential of bone healing. Therefore, implant surface modification study that aims at enhancing bone formation to further improve short- and long-term clinical outcomes in osteoporosis is necessary. MATERIAL AND METHODS: Fifty female, 3-month-old mice were included in this study. Osteoporosis was induced by ovariectomy (OVX, test group) in 25 mice. The further 25 mice had ovaries exposed but not removed (SHAM, control group). Seven weeks following the ovariectomy procedures, one customized implant (0.7 × 8 mm) of each surface was placed in each femur for both groups. Implants had either a hydrophobic surface (SAE) or a hydrophilic treatment surface (SAE-HD). Calcium (Ca) and phosphorus (P) content was measured by energy-dispersive X-ray spectroscopy (EDS) after 7 days. The femurs were analyzed for bone-to-implant contact (BIC) and bone volume fraction (BV) by nano-computed tomography (nano-CT) after 14 and 28 days. Same specimens were further submitted to histological analysis. Additionally, after 3 and 7 days, implants were removed and cells were collected around the implant to access gene expression profile of key osteogenic (Runx2, Alp, Sp7, Bsp, Sost, Ocn) and inflammatory genes (IL-1ß, IL-10, Tnf-α, and Nos2) by qRT-PCR assay. Statistical analysis was performed by ANOVA and paired t test with significance at P < .05. RESULTS: The amount of Ca and P deposited on the surface due to the mineralization process was higher for SAE-HD compared to SAE on the intra-group analysis. Nano-CT and histology revealed more BV and BIC for SAE-HD in SHAM and OVX groups compared to SAE. Analysis in OVX group showed that most genes (ie, ALP, Runx2) involved in the bone morphogenetic protein (BMP) signaling were significantly activated in the hydrophilic treatment. CONCLUSION: Both surfaces were able to modulate bone responses toward osteoblast differentiation. SAE-HD presented a faster response in terms of bone formation and osteogenic gene expression compared to SAE. Hydrophilic surface in situations of osteoporosis seems to provide additional benefits in the early stages of osseointegration.

Effect of Surgical Installation of Dental Implants on Surface Topography and Its Influence on Osteoblast Proliferation.

Surface treatment alone does not determine the final microtopography of a dental implant, which can be influenced by implant design and the surgical procedure. This study investigated the effect of surgical placement of dental implants with same surface treatments on surface roughness. Three implants (SIN) of each group with different macrogeometries (Strong, Stylus, and Tryon) were analyzed using laser interferometry and scanning electron microscopy to evaluate surface topography. All threaded regions of the implants, namely, top, flank, and valley, were analyzed individually. Relevant surface parameters (S a, S sk, S ku, S tr, and S dq) were calculated for the different regions on each implant before (B) (n = 9) and after (A) (n = 9) placement into porcine rib bones. The behavior and proliferation of a preosteoblastic cell line MC3T3-E1 on titanium surface, cell viability, and osteopontin secretion were evaluated after 24 h, 48 h, and 96 h, also before (n = 18) and after (n = 18) implant placement into porcine ribs bone. As results, the valleys of all implants had an increase in S a values after implant placement. By contrast, the tops of the Stylus A implant and the flanks of the Tryon A implant showed a significant decrease in mean height of the irregularities (S a), 0.16 µm and 1.25 µm, respectively. The Stylus implant presented significantly (p < 0.05) higher asymmetry values on the distribution curve for irregularity heights (S ku) in all regions after insertion into bone (6.99 for tops, 9.54 for flanks, and 17.64 for valleys), indicating a greater preponderance of peaks over valleys. An increase in roughness gradients (S dq) was observed for all macrogeometries after insertion into bone. The cell culture results showed no significant difference (p > 0.05) for all macrogeometries after bone placement. In conclusion, a subtle change in implant surface roughness was detected after insertion into bone for all the macrogeometries, without significantly affecting the cellular parameters studied.

Bisphosphonate treatment and dental implants: A systematic review

BACKGROUND: To analyze articles that studied patients submitted to diphosphonates therapy and who received dental implants before, during or after bisphosphonate (BP) treatment, compared to healthy patients, analyzing the increase of failure and loss of implants or bisphosphonate related osteonecrosis of the jaw (BRONJ) incidence. MATERIAL AND METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement was used in this study. The clinical question in 'PICO' format was: In patients under bisphosphonate therapy, do dental implants placement, compared to healthy patients, increase the failure and loss of implants or bisphosphonate related osteonecrosis of the jaw incidence? PubMed/MEDLINE was searched for articles published up until April 15, 2015 using a combination of MeSH terms and their Entry terms. RESULTS: The search resulted in 375 articles. After selection according to the eligibility criteria, 15 studies fulfilled were included (eight retrospective, one prospective and six case series), with a total of 1339 patients analyzed, 3748 implants placed, 152 loss of implants and 78 cases of BRONJ. CONCLUSIONS: Due to the lack of randomized clinical trials looking at this theme, further studies with longer follow-up are needed to elucidate the remaining questions. Thus, it is wise to be careful when planning dental implant surgery in patients undergoing bisphosphonate therapy because of the risk of developing BRONJ as well as occurring failure of implant. Moreover, complete systemic condition of the patient must be also taking into considering when such procedures are performed

Síndrome da combinação: diagnóstico, prevenção e considerações sobre o tratamento / Combination Syndrome: diagnosis, prevention and treatment considerations

A síndrome da combinação, descrita por Kelly em 1972, apresenta-se a partir de um conjunto de características marcantes que ocorrem quando uma maxila desdentada se opõe a dentes anteriores inferiores naturais. Essa condição clínica é mais comumente encontrada em pacientes que fazem uso de prótese total superior que oclui com dentes naturais anteriores inferiores e prótese parcial removível bilateral inferior. Também conhecida por Síndrome de Kelly, é caracterizada pela perda óssea da região anterior do rebordo superior, extrusão dos dentes naturais anteriores, aumento das tuberosidades maxilares, perda óssea da região posterior do arco inferior sob a base da PPR e hiperplasia papilar da mucosa do palato duro. O correto diagnóstico e tratamento da síndrome são imprescindíveis na obtenção de resultado que, no mínimo, impeça o avanço do quadro. O presente trabalho consiste no relato de caso clínico de uma paciente diagnosticada com Síndrome da Combinação, no qual, além de importantes considerações acerca do diagnóstico, prevenção e tratamento reabilitador dos pacientes portadores dessa síndrome, chama-se atenção para os cuidados cirúrgicos e protéticos específicos que devem estar envolvidos na reabilitação dos pacientes portadores dessa condição.

The combination syndrome, as described by Kelly in 1972, is presented as a set of characteristics that occur when an toothless maxilla is opposed to natural mandibular anterior teeth. This clinical condition is more commonly found in patients who use dentures that occludes with natural lower anterior teeth and bilateral removable partial dentures. Also known as kelly syndrome is characterized by loss of bone anterior region of the upper lip, extrusion of lower natural teeth remaining, increased jaws tuberosities, bone loss of support from the base of removable partial dentures and papillary hyperplasia of the mucosa of the palate hard. Proper diagnosis and treatment of syndrome are essential in achieving a result which at least impedes the progress of the condition. This work is a case report of a patient diagnosed with the combination syndrome, in which, in addition to important considerations about the diagnosis, prevention and rehabilitation treatment of patients with this syndrome, called attention to the specific surgical and prosthetic care that should be involved in the rehabilitation of patients with this condition.

Biological Effects of a Root Conditioning Treatment on Periodontally Affected Teeth--An In Vitro Analysis.

The aim of this study was to evaluated the root surfaces modifications resulted by application of different chemicals agents, and their influence on the fibrin network and fibroblasts attachment. From 96 anterior mandibular human extracted incisor teeth, 192 dentin blocks of buccal and lingual surface were obtained and randomly divided into 6 groups: Cont- control group, which received no treatment; Root surface scaling and root planing (Srp); Citric acid-Srp; EDTA-Srp; Tetracycline capsule-Srp; Tetracycline gel-Srp. After dentin treatments the specimens were analyzed as follows: 1) demineralization level and residues of the product by scanning electron microscopy (SEM); 2) adhesion of blood components after 20 min of surface treatment by SEM; 3) fibroblast attachment after 24 h by SEM; 4) cell metabolism after 24 h by MTT assay. Data were analyzed using Fisher Exact, One-way ANOVA test followed by Dunn's test, Tukey test and Dunnett test (α=0.05). Citric acid, EDTA and Tetracycline gel resulted in adequate demineralization with no completely smear layer and smear plug removal on root dentin surface. Tetracycline capsule produced great tetracycline residues with several demineralization areas. Tetracycline gel and EDTA groups presented more fibroblast fixation than other experimental groups. The highest mean blood clot adhesion score was observed in roots treated with tetracycline gel. EDTA and Tetracycline gel surface treatment removed the smear layer over dentin surface and promoted adhesion of fibrin network and fibroblast cells attachment.

Biological Effects of a Root Conditioning Treatment on Periodontally Affected Teeth - An In Vitro Analysis

Abstract The aim of this study was to evaluated the root surfaces modifications resulted by application of different chemicals agents, and their influence on the fibrin network and fibroblasts attachment. From 96 anterior mandibular human extracted incisor teeth, 192 dentin blocks of buccal and lingual surface were obtained and randomly divided into 6 groups: Cont- control group, which received no treatment; Root surface scaling and root planing (Srp); Citric acid-Srp; EDTA-Srp; Tetracycline capsule-Srp; Tetracycline gel-Srp. After dentin treatments the specimens were analyzed as follows: 1) demineralization level and residues of the product by scanning electron microscopy (SEM); 2) adhesion of blood components after 20 min of surface treatment by SEM; 3) fibroblast attachment after 24 h by SEM; 4) cell metabolism after 24 h by MTT assay. Data were analyzed using Fisher Exact, One-way ANOVA test followed by Dunn's test, Tukey test and Dunnett test (α=0.05). Citric acid, EDTA and Tetracycline gel resulted in adequate demineralization with no completely smear layer and smear plug removal on root dentin surface. Tetracycline capsule produced great tetracycline residues with several demineralization areas. Tetracycline gel and EDTA groups presented more fibroblast fixation than other experimental groups. The highest mean blood clot adhesion score was observed in roots treated with tetracycline gel. EDTA and Tetracycline gel surface treatment removed the smear layer over dentin surface and promoted adhesion of fibrin network and fibroblast cells attachment.

Resumo O objetivo deste estudo foi avaliar modificações nas superfícies radiculares sofridas pela aplicação de diferentes agentes químicos, e sua influência sobre a rede de fibrina e adesão de fibroblastos. A partir de 96 incisivos inferiores humanos, 192 blocos de dentina das superfícies vestibular e lingual foram obtidos e divididos aleatoriamente em 6 grupos: Cont-grupo controle, não recebeu nenhum tratamento; Raspagem e alisamento radicular (RAR); Ácido cítrico-SRP; EDTA-SRP; Tetraciclina em cápsula-SRP; Tetraciclina gel-SRP. Após o tratamento da dentina as espécimes foram analisadas: 1, nível de desmineralização e resíduos do produto por microscopia eletrônica de varredura (MEV); 2, adesão dos componentes sanguineos após 20 min na tratamento de superfície por SEM; 3, adesão de fibroblastos após 24h por SEM; 4, o metabolismo celular após 24 h por ensaio MTT. Os dados foram analisados por Fisher Exact, teste one-way ANOVA, seguido pelo teste de Dunn, teste de Tukey e teste de Dunnett (α = 0,05). O ácido cítrico, EDTA e gel tetraciclina resultaram na adequada desmineralização sem remoção completa de camada de smear layer e smear plug sobre a superfície da dentina radicular. Cápsula de tetraciclina produziu grandes resíduos de tetraciclina com várias áreas de desmineralização. Os grupos Gel de tetraciclina e EDTA apresentaram maior adesão de fibroblastos do que os demais grupos experimentais. O maior score de adesão de coágulo sanguineo foi observado nas superfícies tratadas com gel de tetraciclina. EDTA e Gel de tetraciclina removeram a camada de smear layer sobre a superfície da dentina e promoveu adesão da rede de fibrina e de fibroblastos.

Local Drug Delivery Systems in the Treatment of Periodontitis: A Literature Review.

In order to complement non-surgical therapy in periodontitis, there are multiple options of antimicrobials, such as metronidazole, chlorhexidine, minocycline, doxycycline and tetracycline, which can be locally delivered into the mucosa. These drugs are used in periodontal pockets and can inhibit or eliminate periodontopathogenic microorganisms as well as modulate the inflammatory response of tissues. However, limited data are available concerning the relationship between effect, efficacy and clinical status of the periodontium. This review aims to evaluate the effect and the efficacy of five types of local drug delivery systems in clinical parameters of periodontology. Researched papers using MEDLINE via PubMed, and LILACS databases related to five types of local drug delivery systems as chlorhexidine gluconate, doxycycline hyclate, metronidazole gel, minocycline ointment and tetracycline fibers, were reviewed aiming to address the mechanism of action and the evidence of clinical effectiveness of adjunctive use of these antimicrobials following surgical and/or non-surgical therapies. Inclusion criteria defined that articles must be randomized controlled trials performed in humans and published between 1996 and 2014. The adjunctive use of local drug delivery systems with controlled release properties may provide a defined, but limited, beneficial response on periodontal pockets. Furthermore, local drug delivery as an active treatment or maintenance therapy depends on clinical findings, responses to treatment described in the literature, desired clinical outcomes, and patients' dental and medical histories, including their past usage of antimicrobials.

External Hexagon Deformation in Implants Subjected to Internal Torque.

Failures may occur in the connections of dental implants, especially in external hexagon (EH). Due to the deformations in this portion of implants, this study aimed to evaluate the levels of deformation of EH connections subjected to internal toque. Two types of implants were used: N group and S group. Torques of 0, 32, 45, 60 and 80 Ncm were applied to the N group, and torques of 0, 30, 40, 60 and infinite Ncm were applied to the S group implants. The internal distance (ID), internal area (IA) and external area (EA) of the EH were obtained from digital pictures, which were analyzed by a specific software. Statistical analysis was performed by the Scott-Knott test. The results showed that the higher the torque applied, the greater were the changes in the evaluated dimensions in both groups. In the S group, torque levels equal or greater than 40 Ncm and 30 Ncm caused greater deformation of EA and IA respectively, while in the N group, torque levels equal or greater than 60 Ncm and 32 Ncm caused greater deformation of EA and IA respectively. Levels of deformation were greater in the S group as compared with the N group. These findings suggest that the IA, EA and ID of the EH may be affected by different internal torque levels.

Effect of Macrogeometry on the Surface Topography of Dental Implants.

PURPOSE: Because the microtopography of titanium implants influences the biomaterial-tissue interaction, surface microtexturing treatments are frequently used for dental implants. However, surface treatment alone may not determine the final microtopography of a dental implant, which can also be influenced by the implant macrogeometry. This work analyzed the effects on surface roughness parameters of the same treatment applied by the same manufacturer to implants with differing macro-designs. MATERIALS AND METHODS: Three groups of titanium implants with different macro-designs were investigated using laser interferometry and scanning electron microscopy. Relevant surface roughness parameters were calculated for different regions of each implant. Two flat disks (treated and untreated) were also investigated for comparison. RESULTS: The tops of the threads and the nonthreaded regions of all implants had very similar roughness parameters, independent of the geometry of the implant, which were also very similar to those of flat disks treated with the same process. In contrast, the flanks and valleys of the threads presented larger irregularities (Sa) with higher slopes (Sdq) and larger developed surface areas (Sdr) on all implants, particularly for implants with threads with smaller heights. The flanks and valleys displayed stronger textures (Str), particularly on the implants with threads with larger internal angles. CONCLUSION: Parameters associated with the height of the irregularities (Sa), the slope of the asperities (Sdq), the presence of a surface texture (Str), and the developed surface area of the irregularities (Sdr) were significantly affected by the macrogeometry of the implants. Flat disks subjected to the same surface treatment as dental implants reproduced only the surface topography of the flat regions of the implants.

External Hexagon Deformation in Implants Subjected to Internal Torque

Failures may occur in the connections of dental implants, especially in external hexagon (EH). Due to the deformations in this portion of implants, this study aimed to evaluate the levels of deformation of EH connections subjected to internal toque. Two types of implants were used: N group and S group. Torques of 0, 32, 45, 60 and 80 Ncm were applied to the N group, and torques of 0, 30, 40, 60 and infinite Ncm were applied to the S group implants. The internal distance (ID), internal area (IA) and external area (EA) of the EH were obtained from digital pictures, which were analyzed by a specific software. Statistical analysis was performed by the Scott-Knott test. The results showed that the higher the torque applied, the greater were the changes in the evaluated dimensions in both groups. In the S group, torque levels equal or greater than 40 Ncm and 30 Ncm caused greater deformation of EA and IA respectively, while in the N group, torque levels equal or greater than 60 Ncm and 32 Ncm caused greater deformation of EA and IA respectively. Levels of deformation were greater in the S group as compared with the N group. These findings suggest that the IA, EA and ID of the EH may be affected by different internal torque levels.

Falhas podem ocorrer em conexões de implantes dentários, em especial em hexágonos externos (EH). Devido à ocorrência de deformação nesta porção dos implantes, este estudo objetivou avaliar os níveis de deformação de conexões EH submetidas ao torque interno. Dois tipos de implantes foram utilizados: grupo N e grupo S. Foram aplicados torques de 0, 32, 45, 60 e 80 Ncm nos implantes do grupo N e torques de 0, 30, 40, 60 Ncm e infinito nos implantes do grupo S. Medidas referentes à distância interna (ID), área interna (AI) e área externa (AE) foram obtidas por meio de fotos digitais analisadas em software. A análise estatística foi feita pelo teste de Scott-Knott. Os resultados demonstraram que quanto maior o torque aplicado, maior a alteração de todas as dimensões avaliadas em ambos os grupos. No grupo S, torques iguais ou superiores a 40 Ncm e 30 Ncm causaram maior deformação na AE e AI respectivamente, enquanto no grupo N, torques iguais ou superiores a 60 Ncm e 32 Ncm causaram maior deformação na AE e AI respectivamente. Os níveis de deformação foram maiores no grupo S em comparação ao grupo N. Nossos resultados indicam que a AI, a AE e a DI do EH podem ser influenciadas pelos diferentes torques internos.

The influence of interproximal contact on implant-supported fixed partial dentures in the posterior jaw: a photoelastic analysis.

The aim of this study was to analyze the effect of the separation of prosthetic crowns from fixed partial dentures by means of stress gradient evaluation. Three photoelastic models were created to examine contiguous implants with varying contact between the crowns (contact point [CP], contact surface [CS], splinted [SP]). The SP group presented the best results, followed by the CS group, indicating that the use of splinted prosthetic crowns and crowns with broad surface contacts is viable when considering the stress values.

Avaliação da capacidade da membrana absorvível atuar como carreadorde quimioterápicos / Capacity assessment of absorbable membrane acting as a carrier for chemotherapeutics

Objetivo: A exposição da membrana durante procedimentos regenerativos periodontais pode causar contaminação e complicações pós-operatórias. Este estudo avaliou a capacidade de uma membrana absorvível atuar como carreador de quimioterápicos. Material e Métodos: Noventa amostras de membranas absorvíveis de origem xenógena, da marca Genius/Baummer, foram previamente impregnadas, sendo 45 com doxiciclina e 45 com cloridrato de tetraciclina, e dispostas em placas de cultura contendo microrganismos aeróbios e anaeróbios. O período experimental foi de 5 semanas, com avaliações regulares a cada semana com objetivo de identificar a integridade das membranas e a capacidade de inibir o crescimento bacteriano pela presença dos halos de inibição. Resultados: Ao final do experimento constatou-se que para culturasaeróbias o período mínimo de inibição foi de 21 dias, para anaeróbiasfoi de 28 dias e os resultados foram estatisticamente superiores para a doxiciclina. Conclusão: Ambas as membranas apresentam habilidade de inibição bacteriana, confirmando a possibilidade das membranas testadas serem utilizadas como carreadores de agentes antimicrobianos, especialmente para a doxiciclina.

Objective: The membrane exposure during periodontal regenerative procedures can lead to contamination and postoperative complications. This study evaluated the ability of an absorbable membrane acting as a carrier for chemotherapeutic. Materials and Methods: Samples of absorbable bovine bone membranes, which were previously impregnated with doxycycline and tetracycline hydrochloride, were placed in culture plates containing aerobic and anaerobic microorganisms. The experimental period lasted 5 weeks, with samples analyzed weekly during this period. Results: At the end of the experiment it was found that for aerobic culturesthe minimum period of inhibition was 21 days and for anaerobic was 28 days; the results were statistically superior to doxycycline. Conclusion: Both membranes have the ability of bacterial inhibition, confirming the ability of the tested membranes been used as carriers of antimicrobial agents, especially for doxycycline.

Biocompatibility of three bioabsorbable membranes assessed in FGH fibroblasts and human osteoblast like cells culture.

OBJECTIVES: Specific physical and chemical features of the membranes may influence the healing of periodontal tissues after guided tissue regeneration (GTR). The aim of the present investigation was to analyze the biological effects of three bioabsorbable membranes. The hypothesis is that all tested membranes present similar biological effects. METHODS: Human osteoblast like-cells (SaOs-2) and gingival fibroblasts FGH (BCRJ -RJ) were cultured in DMEM medium. The viability of the cells cultured on the membranes was assesses using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Quantitative determination of activated human Transforming Growth Factor beta 1 (TGF-ß1) on the supernatants of the cell culture was observed. Samples were examined using scanning electron microscope (SEM). RESULTS: SaOs2, in 24 hours, PLA group showed higher values when compared to other groups (P < 0.05). All groups presented statistical significance values when compared two times. In 4 h and 24 h, for the fibroblasts group, significantly difference was found to PLA membrane, when compared with the other groups (p < 0.05). For TGFß1 analyzes, comparing 4 and 24 h, for the osteoblast supernatant, COL1 and PLA groups showed statistically significant difference (p <0,008). On the analysis of culture supernatants of fibroblasts, in 24 hours, only PLA group presented significant difference (p = 0,008). CONCLUSIONS: The biomaterials analyzed did not show cytotoxicity, since no membrane presented lower results than the control group. PLA membrane presented the best performance due to its higher cell viability and absorbance levels of proliferation. Both collagen membranes showed similar results either when compared to each other or to the control group.

Effects of bleaching agents and adhesive systems in dental pulp: a literature review

The dental pulp may be exposed to several irritants that are potentially noxious to the health and functions of this tissue. Each type of irritant or injury has different effects on the pulp, which are generally characterized by acute inflammation, chronic inflammation or necrosis. Common examples of irritants are dental caries, cavity preparation procedures, traumatic injuries, and chemical substances like bleaching agents and adhesive systems. The present study aimed to review the current knowledge about the effect of bleaching agents and adhesive systems in the human dental pulp. The review covered literature from 2004 to 2009, and only relevant manuscripts were included. Hand search of the references completed the review. Based on literature review, it may be concluded that all dental procedures associated with bleaching agents or adhesive systems involve risks to cause pulp damage. However, these risks can be minimized if the causal factors were known and avoided.

Cytotoxicity of bovine and porcine collagen membranes in mononuclear cells.

This study compared the cytotoxicity and the release of nitric oxide induced by collagen membranes in human mononuclear cells. Peripheral blood was collected from each patient and the separation of mononuclear cells was performed by Ficoll. Then, 2x10(5) cells were plated in 48-well culture plates under the membranes in triplicate. The polystyrene surface was used as negative control. Cell viability was assessed by measuring mitochondrial activity (MTT) at 4, 12 and 24 h, with dosage levels of nitrite by the Griess method for the same periods. Data had non-normal distribution and were analyzed by the Kruskal-Wallis test (p<0.05). Statistically significant differences (p<0.05) were observed between the membranes and the control in the experimental period, although there was a significant reduction in viability over time (p<0.01). At 4 and 12 h, the porcine membrane induced a higher release of nitrite compared with the control and bovine membrane, respectively (p<0.01), and this difference was maintained at 24 h (p<0.05). This in vitro study showed that the porcine collagen membrane induces an increased production of proinflammatory mediators by mononuclear cells in the first hours of contact, decreasing with time.

Cytotoxicity of bovine and porcine collagen membranes in mononuclear cells

This study compared the cytotoxicity and the release of nitric oxide induced by collagen membranes in human mononuclear cells. Peripheral blood was collected from each patient and the separation of mononuclear cells was performed by Ficoll. Then, 2x10(5) cells were plated in 48-well culture plates under the membranes in triplicate. The polystyrene surface was used as negative control. Cell viability was assessed by measuring mitochondrial activity (MTT) at 4, 12 and 24 h, with dosage levels of nitrite by the Griess method for the same periods. Data had non-normal distribution and were analyzed by the Kruskal-Wallis test (p<0.05). Statistically significant differences (p<0.05) were observed between the membranes and the control in the experimental period, although there was a significant reduction in viability over time (p<0.01). At 4 and 12 h, the porcine membrane induced a higher release of nitrite compared with the control and bovine membrane, respectively (p<0.01), and this difference was maintained at 24 h (p<0.05). This in vitro study showed that the porcine collagen membrane induces an increased production of proinflammatory mediators by mononuclear cells in the first hours of contact, decreasing with time.

Neste estudo foi comparada a citoxicidade e a liberação de nitrito induzidos por membranas de colágeno bovino e suíno em células mononucleares humanas. Foram coletados sangue periférico de cada paciente, e realizada separação de mononucleares por gradiente de Ficoll. Um total de 2x10(5) células foram plaqueadas em placas de cultura de 48 poços sob as membranas, em triplicata. O poço sem membrana serviu como controle negativo. A viabilidade celular foi avaliada medindo a atividade mitocondrial (MTT) em 4,12 e 24 h, com dosagens dos níveis de nitrito pelo método de Griess nos mesmos períodos. As amostras não apresentaram distribuição normal, sendo realizado o teste de Kruskal-Wallis (p<0,05). Foram observadas diferenças estatisticamente significantes entre as membranas e o controle nos período analisados (p<0,05), embora tenha ocorrido redução da viabilidade em função do tempo (p<0,01). Em 4 e 12 h a membrana suína induziu maior liberação de nitrito comparado ao controle e à membrana bovina, respectivamente (p<0,01). Tal diferença foi mantida em 24 h (p<0,05). Este estudo in vitro demonstrou que a membrana colágena suína induz uma maior produção de mediador pró-inflamatório pelas células mononucleares nas primeiras horas de contato, diminuindo com o tempo.

Terapia periodontal de suporte: objetivos, procedimentos e intervalos / Supportive periodontal therapy: objectives, procedures and intervals

A Terapia Periodontal de Suporte (TSP) denota a necessidade básica dos procedimentos terapêuticos para que os pacientes, por meio de esforços próprios, possam controlar a infecção periodontal, sendo considerada abordagem que está diretamente relacionada com o sucesso da terapia periodontal como um todo. Inúmeras experiências clínicas sobre os efeitos em longo prazo do tratamento de periodontite têm demonstrado que manutenção profissional cuidadosa pós-terapêutica é parte integrante do tratamento periodontal, constituindo o único meio de garantir a manutenção por longo período dos efeitos benéficos da terapia. Assim, o objetivo desse artigo é revisar alguns aspectos relacionados à TSP, incluindo filosofia e periodicidade do tratamento, índices para controle periodontal, abordagem profissional, recursos e técnicas disponíveis bem como o processo de reavaliação de pacientes. A avaliação desses tópicos permite afirmar que a TSP é pré-requisito indiscutível para garantir resultados benéficos dos tratamentos com manutenção dos níveis de inserção clínica por longos períodos de tempo, mesmo que abordagens em relação à avaliação contínua do risco nos níveis do paciente, dos dentes e dos sítios dos dentes representem desafio para o conceito da TSP.

Supportive Periodontal Therapy (SPT) denotes the basic need of therapeutic procedures in order patients can control periodontal infection through their own efforts, considering the approach that is directly related to the success of the periodontal therapy as a whole. Several clinical experiences on long-term effects of periodontitis treatments have shown that a careful professional post-therapeutic maintenance therapy is part of the periodontal treatment, consisting in the only means of assuring the maintenance of the therapy beneficial effects in long term. This paper aims to review a few aspects related to SPT, including philosophy and frequency of treatment, periodontal control indexes, professional approach, available resources and techniques, as well as the process of reassessing patients. The analysis of those topics allows us to state that SPT is an undeniable prerequisite to ensure beneficial outcomes of periodontal treatment with maintenance of clinical attachment levels for long periods, even though approaches to continuous assessment of the patient?s risk levels, teeth and tooth sites pose a challenge to SPT concept.

Effect of bone loss simulation and periodontal splinting on bone strain: Periodontal splints and bone strain.

OBJECTIVES: The influence of bone loss and periodontal splinting on strains in supporting bone is still not well understood. The aim of this study was to analyse the effect of bone loss and periodontal splints on strains in an anterior mandible structure. METHODS: Ten anterior mandible models were fabricated using polystyrene resin. Eighty human teeth were divided in 10 groups (right first premolar to left premolar) and embedded in simulated periodontal ligament. Strain gauges were attached to the buccal and lingual mandible surfaces. The models were sequentially tested for 7 conditions: no bone alterations and no splinting; 5mm of bone loss between canine teeth; bone loss associated with resin splint between canine teeth; bone loss with wire splint; bone loss with wire/resin splint; bone loss with extracoronal fibre-glass/resin splint; and bone loss with intracoronal fibre-glass/resin splint. Oblique loads (50, 100, and 150N) were applied on the teeth. Data were analysed using 3-way ANOVA and Scheffe's test (α=.05). RESULTS: Strains on buccal surface were higher than on lingual surface. Bone loss resulted in strain increase at 100 and 150N loading. Dental splinting with resin resulted in strain values similar to the control levels. CONCLUSIONS: Bone loss increased strain mainly in the buccal region. Dental splints with adhesive system and composite resin produced lower bone strains irrespective of occlusal load.

Effect of periodontal therapies on indirect restoration: a scanning electron microscopic analysis.

The aim of this study was to evaluate the influence of different periodontal therapies on the integrity of indirect restorations by scanning electron microscopy (SEM). Sixty single-rooted bovine teeth were selected and randomly assigned to 12 groups. Inlay cavities were prepared in the cervical region on the center of the cementoenamel junction, and were restored with laboratory processed resin and luted with a resin cement. Twelve periodontal therapies were used (n= 5): C: control (no treatment); MS: manual scaling with Gracey curettes; US: ultrasonic scaling; PP: prophylaxis with prophylactic paste; PS: prophylaxis with pumice-stone; SBJ: sodium bicarbonate jet; MS/PP; MS/PS; MS/SBJ; US/PP; US/PS; US/SBJ. The specimens were prepared and analyzed by SEM. SEM micrographs at x100 to x1000 magnification were obtained from the surface of the laboratory resin and the interface of the indirect restorations. The images were evaluated by 3 skillful, calibrated, blinded observers as to the presence of grooves, microcavities and fracture of margins. The results showed that PS produced groves on restoration surface. MS and US produced groves and marginal fractures on the restorations. SBJ resulted in resin cement degradation. These results suggest that except for PS, all procedures had deleterious effects on the marginal integrity of indirect restorations.