Low-intensity laser phototherapy enhances the proliferation of dental pulp stem cells under nutritional deficiency

Abstract Dental trauma in immature permanent teeth can damage pulp vascularization, which leads to necrosis and cessation of apexogenesis. Studies on tissue engineering using stem cells from human exfoliated deciduous teeth (SHEDs) have yielded promising results. Laser phototherapy (LPT) is able to influence the proliferation and differentiation of these cells, which could improve tissue engineering. SHEDs (eighth passage) were seeded into 96-well culture plates (103 cells/well) and were grown in culture medium supplemented with 15% defined fetal bovine serum (FBS) for 12 h. After determining the appropriate nutrition deficiency status (5% FBS), the cells were assigned into four groups: 1) G1 - 15% FBS (positive control); 2) G2 - 5% FBS (negative control); 3) G3 - 5% FBS+LPT 3 J/cm2; and 4) G4 - 5% FBS+LPT 5 J/cm2. For the LPT groups, two laser irradiations at 6 h intervals were performed using a continuous wave InGaAlP diode laser (660 nm, with a spot size of 0.028 cm2, 10 mW) in punctual and contact mode. Cell viability was assessed via an MTT reduction assay immediately after the second laser irradiation (0 h) and 24, 48, and 72 h later. We found that G3 and G4 presented a significantly higher cell growth rate when compared with G2 (p < 0.01). Moreover, G4 exhibited a similar cell growth rate as G1 throughout the entire experiment (p > 0.05). These findings indicate that LPT with 5 J/cm2 can enhance the growth of SHEDs during situations of nutritional deficiency. Therefore, LPT could be a valuable adjunct treatment in tissue engineering when using stem cells derived from the dental pulp of primary teeth.

Chenopodium ambrosioides L. extract prevents bone loss

ABSTRACT PURPOSE: To evaluate the effect of the Chenopodium ambrosioides L (mastruz) extract for preventing bone loss and bone metabolism in ovariectomized rats. METHODS: Twelve rats were subjected to bilateral ovariectomy for inducing osteoporosis. After surgery, they were divided into two groups: Ovariectomy-control group (G1, n=6), receiving 0.5 ml distilled water by gavage for 30 days, and Ovariectomy plus mastruz group (G2, n=6), receiving 0.5 ml of the hydroalcoholic extract of mastruz at 10% concentration (50mg) daily, for the same period. Then, the blood of the animals was collected for further biochemical analysis (liver function) and tibia and liver were removed for histological and histomorphometric analyses. RESULTS: The cortical bone was significantly larger in the G2 than G1, whereas G1 presented the highest amount of adipocytes in the bone marrow (p<0.05). The blood levels of aspartate aminotransferase, triglycerides and cholesterol were significantly higher, whereas globulin and lactate dehydrogenase were smaller in G2 than G1. CONCLUSION: The hydroalcoholic extract of mastruz has effects on bone metabolism by changing blood proteins and enzymes and preventing both bone loss and the substitution of bone marrow cells by.

Atraumatic restorative treatment - glass ionomer sealants survival after a postgraduate training program in Ecuador: 2-year follow-up

This study aimed to evaluate the survival of atraumatic restorative treatment high-viscosity glass ionomer sealants (ART-hvGIS) and its relationship with carious lesions incidence in underserved communities of Ecuador. A total of 483 first permanent molars with ART-hvGIS were included after treatment, in which fifteen students of the First Preventive Dentistry Post Graduate Program of Universidad Central del Ecuador assisted 176 schoolchildren, from 5 to 12 year-old. All the students had previously participated in a training course in ART approach. After one and two years follow-up, schoolchildren were reevaluated in relation to sealants retention and new carious lesions development. After first year of evaluation ART-hvGIS retention rate was about 30% and after second year 20%. Incidence of carious lesions was 4.0 and 3.4% after first and second periods, respectively. Although there was an extensive ART-hvGIS loss, carious lesions incidence was low in both the periods of evaluation. ART-hvGIS might be an important key to prevent tooth decay in underserved communities.

Choice of toothpaste for the elderly: an in vitro study

Hyposalivation and dental root exposure in the elderly are problems that require special oral care. In this context, the characteristics of certain toothpastes are of particular importance. Thus, the aim of this study was to evaluate the cytotoxicity and dentin wear caused by seven different toothpastes. For dentin wear analysis, 40 root dentin specimens were submitted to 20,000 brushing cycles with the different toothpastes and distilled water (control group-CG), using a brushing machine. Dentin surface loss (SL) was measured by contact profilometer. The cytotoxicity of each toothpaste was tested using cultured fibroblasts submitted to a cell-culture-conditioned medium. Fresh medium served as the control. Cell viability was assessed by MTT assay after 24 h of contact with the conditioned media. The data were analyzed statistically by ANOVA, followed by Tukey’s test (p < 0.05). The SL of the CG was minimal and significantly lower than that of the Oral B Pro Health (OBPH) group (p < 0.05). All other groups presented SL in between that of the CG and the Oral B Pro Health OBPH group, except for the Sensodyne (SEN) group, which presented SL similar to that of CG (p = 0.05). The SEN group presented a percentage of viable cells similar to that of CG: between 60-89%. All the other toothpastes showed high cytotoxicity, with cell viability less than 50% of the CG. Considering study limitations, we concluded that only one of the seven tested toothpastes exhibited the most desirable toothpaste characteristics for the worldwide growing elderly population (e.g. low cytotoxicity and low-abrasive potential).

Cytotoxicity of substances leached from a root canal sealer based on mineral trioxide aggregate

Objetivo: Com base nas características biológicas e físico-químicas do agregado de trióxido mineral (MTA), este seria o material mais adequado para a obturação do canal radicular. No entanto, esse material apresenta baixo escoamento e, consequentemente, difícil manipulação. O MTA Fillapex (MTA-F) foi criado na tentativa de combinar as propriedades físico-químicas do cimento endodôntico com as propriedades biológicas do MTA. No entanto, os estudos sobre as características biológicas do MTA-F ainda são controversos. Dessa forma, este estudo teve como objetivo analisar in vitro a citotoxicidade do MTA-F. Materiais e Métodos: fi broblastos gengivais foram cultivados em Dulbecco’s modifi ed Eagle Medium (DMEM) e submetidos ao meio de cultura condicionado pelo MTA ou MTA-F. Esse meio condicionado continha substâncias liberadas pelos cimentos endodônticos. Células cultivadas em meio fresco serviram como controle positivo. A viabilidade celular foi avaliada por ensaio do MTT após 1, 3, 5 e 7 dias. Os dados obtidos foram comparados por análise de variância (ANOVA) seguida pelo teste de Tukey (p < 0,05). Resultados: As células submetidas ao meio condicionado pelo MTA apresentaram curva de crescimento celular semelhante à das células do grupo controle. Para o grupo MTA-F, não houve crescimento celular e foi observado um número de células viáveis signifi cativamente menor do que o dos demais grupos durante todo o experimento. Conclusão: Substâncias liberadas a partir de MTA-F não permitiram o crescimento celular, mostrando que esse cimento endodôntico à base de MTA é altamente citotóxico. A característica de biocompatibilidade do MTA pode ser perdida com o MTA-F e comprometer o sucesso do tratamento endodôntico.

Aim: Based on its biological and physicochemical characteristics, mineral trioxide aggregate (MTA) could be considered the most appropriate material for root canal obturation; nevertheless, handling of MTA is not easy. The MTA Fillapex (MTA-F) was created in an attempt to combine the physicochemical properties of a root canal sealer with the biological properties of MTA. However, the studies on the biological characteristics of MTA-F are still controversial. Thus, this study aimed to analyze the cytotoxicity of MTA-F. Materials and Methods: Cultured human gingival fi broblasts were grown in Dulbecco’s modifi ed Eagle Medium (DMEM) and submitted to a cell culture medium conditioned by MTA or MTA-F. The conditioned medium contained substances leached from the root canal sealers. Cells grown on a fresh medium served as a positive control. Cell viability was assessed by MTT assay at 1, 3, 5 and 7 days. Data was compared by ANOVA followed by Tukey’s test (p < 0.05). Results: Cells submitted to media conditioned by MTA presented a cell growth curve similar to that of the control cells. For the MTA-F group, cell growth was not observed and cell viability was signifi cantly lower than for the other groups during the entire experiment. Conclusion: Substances leached from MTA-F did not allow cell growth, indicating that this MTA-based root sealer is highly cytotoxic. The biocompatibility characteristic of MTA can be lost with MTA-F, and may compromise the endodontic treatment outcome.

Effect of laser phototherapy in the prevention and treatment of chemo-induced mucositis in hamsters

The aim of this study was to investigate the effect of laser phototherapy (LPT) in the prevention and/or treatment of oral mucositis induced by 5-fluorouracil (5-FU; Eurofarma, São Paulo, Brazil) in hamsters. Ninety-six hamsters were divided into four groups (n = 24): Control (no treatment); Preventive [LPT from day (D) D-5 to D+5]; Therapeutic (LPT from D+5 to D+15); and Combined (preventive plus therapeutic LPT from D-5 to D+15). The animals received an intraperitoneal injection of 5-FU on Days 0 and 2. The pouch mucosa was scratched on Days 3 and 4. The irradiation parameters were: indium-gallium-aluminum-phosphide (InGaAlP) diode laser (MM Optics, São Carlos, Brazil) (660 nm), beam area of 0.036 cm2, 40 mW, 1.11 W/cm2, 6.6 J/cm2, power density applied daily of 39.6 J/cm2, in punctual mode (six points and six seconds per point) and contact mode, one application per day. The animals were sacrificed on Days 0, 5, 10 and 15 (n = 6) and weighed, and the pouch mucosa was removed for histopathological analysis. Clinical and corresponding histological scores were compared using ANOVA and Tukey's test (p ≤0.05). Similar weight losses ranging from 5% to 10% occurred in all groups. The therapeutic group had significantly lower clinical and histological scores than the other groups at Day 10. This study showed that positive effects on oral mucositis management were obtained only when LPT was applied in the therapeutic protocol (from D+5 to D+15 after chemotherapy).

Cytotoxicity of non-vital dental bleaching agents in human gingival fibroblasts / Avaliação da citotoxicidade de agentes clareadores de uso interno sobre fibroblastos gengivais humanos

Objective: The aim of this study was to compare several non-vital dental bleaching agents for their in vitro cytotoxicity to human gingival fibroblasts primary cell line. Methods: The cells were cultivated in DMEM and were seed in plates of 96 wells; then, it was exposed to the conditioned medium according to the experimental groups (n = 12): G1 - SP (sodium perborate) + distilled water; G2 - SP + 20% CP (carbamide peroxide); G3 - 20% CP; G4 - SP + 35% HP (hydrogen peroxide); G5 - 35% HP. In the control group (n = 12), corresponded to the curve of cell growth and viability, the cells did not receive any treatment. Cell viability was measured photometrically using a MTT assay after a 24 h and 48 h of exposure period. Data were submitted to ANOVA and Tukey’s tests. Results: All the experimental groups presented high cytotoxicity statically in comparison to the control group. The rank of the most to the least toxic material after 24 h was: SP + DW > 35% PH > PS + 20% PC > PS + 35% PH > 20% PC; and after 48 h was: SP + DW > PS + 20% PC > 35% PH > PS + 35% PH > 20% PC. Conclusion: All the bleaching agents had presented cytotoxicity effects, reducing significantly the cell viability, however, in the conditions that the study was conducted the association of sodium perborate with distilled water was the most toxic bleaching agent

Objetivo: O objetivo deste estudo foi comparar a citotoxicidade de agentes clareadores de uso interno em linhagem primária de fibroblastos humanos. Material e Método: As células foram cultivadas em meio DMEM e semeadas em placas de 96 poços. Em seguida, foram expostas aos meios de cultura condicionados de acordo com os grupos experimentais (n = 12): G1 - PS (perborato de sódio) + água destilada; G2 - PS + PC 20% (peróxido de carbamida); G3 - PC 20% ; G4 - PS + PH 35% (peróxido de hidrogênio); G5 - PH 35%. No grupo controle (n = 12), correspondente à curva de crescimento e viabilidade celular, as células não receberam nenhum tratamento. A viabilidade celular foi verificada por espectofotômetro utilizando o ensaio de MTT, após um período de 24 e 48 h de exposição aos agentes clareadores. Os dados foram submetidos aos testes de ANOVA e Tukey. Resultados: Todos os grupos experimentais apresentaram alta citotoxicidade em relação ao grupo controle. O rank de citotoxicidade dos agestes clareadores após 24 h foi: PS + AD > PH 35% > PS + PC 20% > PS + PH 35% > PC 20% e após 48h foi: PS + AD > PS + PC 20%> 35% PH > PS +PH 35% > 20% PC. Conclusão: Todos os agentes clareadores apresentaram efeitos citotóxicos, reduzindo significativamente a viabilidade da celular. Entretanto, nas condições em que o estudo foi conduzido a associação do perborato de sódio com água destilada, foi o agente clareador mais tóxico

Influence of prior 810-nm-diode intracanal laser irradiation on hydrophilic resin-based sealer obturation

Dentin wall structural changes caused by 810-nm-diode laser irradiation can influence the sealing ability of endodontic sealers. The objective of this study was to evaluate the apical leakage of AH Plus and RealSeal resin-based sealers with and without prior diode laser irradiation. Fifty-two single-rooted mandibular premolars were prepared and divided into 4 groups, according to the endodontic sealer used and the use or non-use of laser irradiation. The protocol for laser irradiation was 2.5W, continuous wave in scanning mode, with 4 exposures per tooth. After sample preparation, apical leakage of 50% ammoniacal silver nitrate impregnation was analyzed. When the teeth were not exposed to irradiation, the RealSeal sealer achieved the highest scores, showing the least leakage, with significant differences at the 5% level (Kruskal-Wallis test, p = 0.0004), compared with AH Plus. When the teeth were exposed to the 810-nm-diode laser irradiation, the sealing ability of AH Plus sealer was improved (p = 0282). In the RealSeal groups, the intracanal laser irradiation did not interfere with the leakage index, showing similar results in the GRS and GRSd groups (p = 0.1009).

Dental pulp stem cells express proteins involved in the local invasiveness of odontogenic myxoma

Little is known about the histogenesis of the odontogenic myxoma (OM). Dental pulp stem cells could be candidate precursors of OM because both OM and the dental pulp share the same embryological origin: the dental papilla. For the purpose of comparing OM and stem cells, this study analyzed the expression of two proteins related to OM invasiveness (MMP-2 and hyaluronic acid) in human immature dental pulp stem cells (hIDPSCs). Three lineages of hIDPSCs from deciduous and permanent teeth were used in this study. Immunofluorescence revealed positive reactions for MMP-2 and hyaluronic acid (HA) in all hIDPSCs. MMP-2 appeared as dots throughout the cytoplasm, whereas HA appeared either as diffuse and irregular dots or as short fibrils throughout the cytoplasm and outside the cell bodies. The gene expression profile of each cell lineage was evaluated using RT-PCR analysis, and HA was expressed more intensively than MMP-2. HA expression was similar among the three hIDPSCs lineages, whereas MMP-2 expression was higher in DL-1 than in the other cell lines. The expression of proteins related to OM invasiveness in hIDPSCs could indicate that OM originates from dental pulp stem cells.

Osteonecrose maxilar associada ao uso de bisfosfonatos / Bisphosphonate-related osteonecrosis of the jaw

Os bisfosfonatos (BFs) têm sido indicados para o tratamento de doenças do metabolismo ósseo. Atualmente, seu emprego terapêutico aumentou e, com ele, os efeitos adversos, dos quais um dos mais importantes é a indução da osteonecrose dos maxilares, uma complicação de difíceis tratamento e solução. Até o presente, não se sabe ao certo qual é o mecanismo de desenvolvimento da osteonecrose dos maxilares induzida por bisfosfonatos (ONMB), nem qual deve ser o tratamento estabelecido perante essa manifestação. Apesar de a literatura apresentar formas variadas de tratamento, não existe um protocolo definido. Apresentamos uma revisão sobre a ONMB, enfocando sua etiopatogenia e as formas reportadas de tratamento.

Bisphosphonates (BPs) have been used for the management of bone metabolic diseases. Currently their therapeutic use has increased, as also have their adverse effects, one of the most important being the bisphosphonate-related osteonecrosis of the jaw (BRONJ), a complication of difficult treatment and solution. Until now, the physiopathology of BRONJ remains unclear, and its treatment is uncertain. Although the literature provides several treatment options, there is no defined protocol. We present a review about BRONJ, focusing on its pathogenesis and its reported forms of treatment.

Dental pulp vascular permeability changes induced by dental bleaching

Aiming to compare the effect of different light sources for dental bleaching on vascular permeability of dental pulps, forty-eight incisors were used. The bleaching agent (35 % hydrogen peroxide) was activated by halogen light; LED (Light Emitting Diode) or LED, followed by laser phototherapy (LPT) (λ = 780 nm; 3 J/cm²). After the bleaching procedures, the animals received an intra-arterial dye injection and one hour later were sacrificed. The teeth were diaphanized and photographed. The amount of blue stain content of each dental pulp was quantified using a computer imaging program. The data was statistically compared (p < 0.05). The results showed a significant higher (p < 0.01) dye content in the groups bleached with halogen light, compared with the control, LED and LED plus LPT groups. Thus, tooth bleaching activated by LED or LED plus LPT induces lesser resulted in increased vascular permeability than halogen light.

Expansive lesion of the anterior mandible in child a case report of calcifying cystic odontogenic tumor

The calcifying cystic odontogenic tumor is an uncommon lesion that occurs in both jaws. This odontogenic neoplasm is generally asymptomatic, found either in routine radiographic examination or when causing bone expansion. The purpose of this report was to describe a case of calcifying cystic odontogenic tumor involving mandible in a 9-year-old girl, as well as discuss the importance of careful diagnostic procedures for the correct final diagnosis and establishment of the most appropriate treatment of this uncommon odontogenic lesion that can affect the patients of the pediatric group.

Micromorphological and hardness analyses of human and bovine sclerotic dentin: a comparative study

The purpose of this study was to test the hypothesis that both human and bovine sclerotic dentin have similar hardness properties, in addition to similar micromorphological characteristics. Sixteen teeth (8 human and 8 bovine) exhibiting exposed dentin in the incisal edge and showing characteristics typical of sclerosis were used. Vickers surface microhardness testing was conducted. Three areas of the dentin surface of each specimen were selected. All teeth were processed for scanning electron microscopy in order to estimate the amount (in percentage) of solid dentin on the sclerotic dentin surface. The data were compared by Student's t test (α = 0.05). The micromorphological and microhardness data were compared by Pearson's linear correlation test (α = 0.05). The mean percentages of solid dentin of human and bovine sclerotic dentin were similar (human 90.71 ± 0.83 and bovine 89.08 ± 0.81, p = 0.18). The mean microhardness value (VHN) of human sclerotic dentin was significantly higher than that of bovine sclerotic dentin (human 45.26 ± 2.92 and bovine 29.93 ± 3.83, p = 0.006). No correlation was found between the microhardness values and the amount of solid dentin in the sclerotic dentin, irrespective of the species considered (human R² = 0.0240, p = 0.714; bovine R² = 0.0017, p = 0.923; and combined R² = 0.038, p = 0.46). We concluded that although both bovine and human sclerotic dentin present a similar amount of solid tissue, human sclerotic dentin presents higher microhardness than bovine sclerotic dentin.

Pulp capping materials exert an effect on the secretion of IL-1β and IL-8 by migrating human neutrophils

Pulp repair is a complex process whose mechanisms are not yet fully understood. The first immune cells to reach the damaged pulp are neutrophils that play an important role in releasing cytokines and in phagocytosis. The objective of this study was to analyze the effect of different pulp-capping materials on the secretion of interleukin-1 beta (IL-1β) and interleukin-8 (IL-8) by migrating human neutrophils. Neutrophils were obtained from the blood of three healthy donors. The experimental groups were calcium hydroxide [Ca(OH)2], an adhesive system (Single Bond), and mineral trioxide aggregate (MTA). Untreated cells were used as control. Transwell chambers were used in performing the assays to mimic an in vivo situation of neutrophil chemotaxis. The pulp-capping materials were placed in the lower chamber and the human neutrophils, in the upper chamber. The cells were counted and the culture medium was assayed using ELISA kits for detecting and quantifying IL-1β and IL8. The data were compared by ANOVA followed by Tukey's test (p < 0.05). The secretion of IL-8 was significantly higher in all groups in comparison to the control group (p < 0.05). The adhesive system group showed higher IL-8 than the MTA group (p < 0.05). The secretion of IL-1β was significantly greater only in the MTA group (p < 0.001). It was concluded that only MTA is able to improve the secretion of IL-1β, and all materials tested increased IL-8 secretion. These results combined with all the other biological advantages of MTA indicate that it could be considered the material of choice for dental pulp capping.

Accuracy of three electronic apex locators in the presence of different irrigating solutions

The present study compared the accuracy of three electronic apex locators (EALs) - Elements Diagnostic®, Root ZX® and Apex DSP® - in the presence of different irrigating solutions (0.9 percent saline solution and 1 percent sodium hypochlorite). The electronic measurements were carried out by three examiners, using twenty extracted human permanent maxillary central incisors. A size 10 K file was introduced into the root canals until reaching the 0.0 mark, and was subsequently retracted to the 1.0 mark. The gold standard (GS) measurement was obtained by combining visual and radiographic methods, and was set 1 mm short of the apical foramen. Electronic length values closer to the GS (± 0.5 mm) were considered as accurate measures. Intraclass correlation coefficients (ICCs) were used to verify inter-examiner agreement. The comparison among the EALs was performed using the McNemar and Kruskal-Wallis tests (p < 0.05). The ICCs were generally high, ranging from 0.8859 to 0.9657. Similar results were observed for the percentage of electronic measurements closer to the GS obtained with the Elements Diagnostic® and the Root ZX® EALs (p > 0.05), independent of the irrigating solutions used. The measurements taken with these two EALs were more accurate than those taken with Apex DSP®, regardless of the irrigating solution used (p < 0.05). It was concluded that Elements Diagnostic® and Root ZX® apex locators are able to locate the cementum-dentine junction more precisely than Apex DSP®. The presence of irrigating solutions does not interfere with the performance of the EALs.

In vitro effect of low intensity laser on the cytotoxicity produced by substances released by bleaching gel

This in vitro study aimed to analyze the effect of different parameters of phototherapy with low intensity laser on the viability of human dental pulp fibroblasts under the effect of substances released by bleaching gel. Cells were seeded into 96 wells plates (1 x 10³ cells/well) and placed in contact with culture medium conditioned by a 35 percent hydrogen peroxide bleaching gel for 40 minutes, simulating the clinical condition of the in-office bleaching treatment. Cells cultured in ideal growth conditions served as positive control group (PC), and the cells grown in conditioned medium and non-irradiated served as negative control group (NC). Cells grown in conditioned medium were submitted to a single irradiation with a diode laser (40 mW, 0.04 cm²) emitting at visible red (660 nm; RL) or near infrared (780 nm; NIR) using punctual technique, in contact mode and energy densities of 4, 6 or 10 J/cm². The cell viability was analyzed through the MTT reduction assay immediately and 24 hours after the irradiation. The data was compared by ANOVA followed by the Tukey's test (p < 0.05). The cell viability increased significantly in 24 hours within each group. The PC presented cell viability significantly higher than NC in both experimental times. Only the NIR/10 J/cm² group presented cell viability similar to that of PC in 24 hours. The phototherapy with low intensity laser in defined parameters is able to compensate the cytotoxic effects of substances released by 35 percent hydrogen peroxide bleaching gel.

Healing and cytotoxic effects of psidium guajava (Myrtaceae) leaf extracts

Aim: The aims of this study were to evaluate the wound healing potential in vivo and the cytotoxic effects in vitro of Psidium guajava (Myrtaceae) leaf extract and commonly used corticosteroids. Methods: The healing effect was studied in vivo by the clinical and histological evaluation of traumatic lesions in the oral mucosa of rats treated with these substances. Each rat received 2 daily applications of the medicine tested and the animals were sacrificed after 1, 3, 5, 7 and 14 days. Tissue sections stained with hematoxylin & eosin were analyzed. The histological evaluation involved a 5-point scoring system based on the degree of healing, ranging from 1 (total repair of epithelium and connective tissue) to 5 (epithelial ulcer and acute inflammatory infiltrate). The Kruskal-Wallis test was used for statistical analysis of the histological scores. For the in vitro toxicity assay, each substance was applied to mucosa fibroblast cell cultures in conditioned media. The media were conditioned by placing the substances in contact with fresh culture medium for 24 h. The cytotoxicity analysis was performed using the MTT assay. Data were analyzed statistically by ANOVA and Tukey’s test at 5% significance level. Results: In vitro, the guava extract caused a decrease in the cell viability and growth when compared to the control and corticosteroids. In vivo, guava extract caused accelerated wound healing from the 3rd day, whereas the corticosteroids delayed tissue repair and were associated with bacterial surface colonization, the presence of micro-abscesses and intense inflammatory infiltrate in the submucosa. Conclusions: Although in a short-term cytotoxicity analysis, the guava extract reduced the cell population in vitro, while in vivo, the extract accelerated wound healing.

Cytotoxicity of substances leached from a conventional and a self-etching adhesive system on human pulp fibroblasts / Citotoxicidade de substâncias liberadas de sistemas adesivos convencional e auto-condicionante sobre fibroblastos de polpa humana

The use of adhesives for direct dental pulp capping is not advisable, due to its harmful effects to the tissue. However, new adhesive systems are often released, and self-etching systems seem to be less toxic than conventional ones. The purpose of this study was to compare the in vitro cytotoxicity of substances leached from calcium hydroxide and two adhesive systems on human dental pulp fibroblasts. Cell culture media conditioned by Calcium Hydroxide (CH), Single Bond (SB), Clearfill Protect Bond primer (CP) or Clearfill Protect Bond resin (CB) were applied to human pulp fibroblasts. Fresh cell culture medium was used in the Control group. The number of viable cells was obtained through the MTT reduction assay. Data were compared by ANOVA and Tukey’s test (p≤0.05). The mean number of viable cells was 3.9x103(±0.75) for the control group, which was similar to those found in the CH group (4.31x103±0.87). Statistical differences were found among the groups (p<0.001), with the cell viability decreasing significantly with SB (0.09x103±0.06) and CP (0.28x103±0.08) when compared to CH and control groups. CB (2.37x103±0.72) was significantly less cytotoxic than CP and SB, but more cytotoxic than CH. It was concluded that Single Bond and Clearfill Protect Bond primer release substances that decrease cell viability of human dental pulp cells in culture. According to this study the use of bonding systems for direct pulp capping is not recommended, since they are cytotoxic

O uso de adesivos dentinários sobre a polpa não é recomendável, devido aos efeitos deletérios provocados sobre o tecido. Entretanto, novos sistemas adesivos são frequentemente lançados, e sistemas autocondicionantes parecem ser menos tóxicos que os sistemas convencionais. O objetivo deste estudo foi comparar in vitro, a citotoxicidade de substâncias liberadas pelo hidróxido de cálcio e dois sistemas adesivos utilizando fibroblastos de polpa humana. Meios de cultura celular condicionados por Hidróxido de cálcio (CH), Single Bond (SB), Clearfill Protect Bond primer (CP) ou Clearfill Protect Bond resin (CB) foram testados em fibroblastos de polpa humana. Meio fresco de cultivo celular foi utilizado no grupo centrole. O número de células viáveis foi obtido através do teste da redução do MTT. Os dados foram comparados por ANOVA e teste de Tukey (p≤0,05). O número médio de células viáveis foi de 3,9x103(±0,75) para o grupo controle, que foi similar ao encontrado para o grupo CH (4,31x103±0,87). Houve diferenças estatísticas entre os grupos (p<0.001), sendo que a viabilidade celular decresceu significantemente com SB (0,09x103±0,06) e CP (0,28x103±0,08), quando comparados ao CH e controle. CB (2,37x103±0,72) foi menos citotóxico que CP e SB, mas mais citotóxico que CH. Conclui-se que o Single Bond e o Clearfill Protect Bond primer liberam substâncias que diminuem a viabilidade celular de fibroblastos humanos em cultura. De acordo com este estudo, o uso de sistemas adesivos para capeamento direto não é recomendado, uma vez que são citotóxicos.

Aspectos microbiológicos, histopatológicos e clínicos da cárie radicular / Microbiology, histopathology and clinical aspects of human root caries

O avanço científico da Odontologia e um maior acesso ao tratamento odontológico fizeram com que o número de pacientes com idade avançada, ainda portadores de dentições naturais, aumentasse. Assim, aumentou também a quantidade de superfícies radiculares expostas, seja por processos fisiológicos, patológicos ou terapêuticos, tornando estas superfícies mais susceptíveis e vulneráveis ao processo de cárie. Este estudo teve como objetivo revisar as características microbiológicas, histopatológicas e clínicas das lesões de cárie radicular. Os estudos revisados apontaram que, dentre os fatores etiológicos dessa patologia, destaca-se a ação do Streptococcus mutans. Contudo, o microrganismo não é o único responsável pelo aparecimento das lesões. A falta de higiene oral, assim como a presença de dieta rica em carboidratos fermentáveis contribui para o desenvolvimento e progressão das cáries de raiz. O tratamento destas lesões é realizado de acordo com a severidade destas, variando desde aplicação de flúor em cáries incipientes, até em restaurações estéticas nos casos mais avançados. Novos estudos, clínicos e laboratoriais, são necessários para se avaliar a longevidade dos tratamentos propostos, principalmente o restaurador.

This study reviewed the microbiological, histopathological and clinical aspects of root caries. Dental caries is one of the most significant health problems facing older adults. More than half of the elderly who are dentate are affected with either coronal or root caries, and caries is the primary cause of tooth loss in this population. However, age per se is not considered to be the main reason for caries development on root surfaces. The same main factors as for coronal caries, ie, cariogenic microorganisms, diet and saliva seem to play important roles in root caries development. Due to different anatomy, histology, and chemical composition of the tissues, there may be a higher risk of caries development on root surfaces than on coronal surfaces. In treatment of root surface caries, a causative treatment strategy should be determined. Prevention should focus on oral hygiene, fluoride exposure, and restriction of intake frequency of foods containing sugars or other easily fermentable carbohydrates. When a more invasive treatment is necessary, caries are removed and the cavities are restored with glass ionomer cement or with flowable composites, where aesthetics procedures become indispensable. New materials and techniques are emerging to help with geriatric preventive and restorative needs.

Distribution of biotypes and leukotoxic activity of Aggregatibacter actinomycetemcomitans isolated from Brazilian patients with chronic periodontitis / Distribuição de biótipos e atividade leucotóxica de Aggregatibacter actinomycetemcomitans isolados de pacientes brasileiros com periodontite crônica

Aggregatibacter actinomycetemcomitans is an important etiologic agent of the periodontitis and is associated with extra-oral infections. In this study, the detection of the ltxA gene as well as the ltx promoter region from leukotoxic A. actinomycetemcomitans isolated from 50 Brazilian patients with periodontitis and 50 healthy subjects was performed. The leukotoxic activity on HL-60 cells was also evaluated. Leukotoxic activity was determined using a trypan blue exclusion method. The 530 bp deletion in the promoter region was evaluated by PCR using a PRO primer pair. A. actinomycetemcomitans was detected by culture and directly from crude subgingival biofilm by PCR using specific primers. By culture, A. actinomycetemcomitans was detected in nine (18 percent) of the periodontal patients and one (2 percent) healthy subject. However, by PCR, this organism was detected in 44 percent of the periodontal patients and in 16 percent of the healthy subjects. It was verified a great discrepancy between PCR detection of the ltx operon promoter directly from crude subgingival biofilm and from bacterial DNA. Only one periodontal sample harbored highly leukotoxic A. actinomycetemcomitans. Moreover, biotype II was the most prevalent and no correlation between biotypes and leukotoxic activity was observed. The diversity of leukotoxin expression by A. actinomycetemcomitans suggests a role of this toxin in the pathogenesis of periodontal disease and other infectious diseases

Aggregatibacter actinomycetemcomitans é um importante agente etiológico da periodontite e produz infecções extra-bucais. Neste estudo, foram detectados os biótipos, o gene ltxA associado à produção de leucotoxina e o promotor ltx em A. actinomycetemcomitans de pacientes com e sem periodontite. A atividade leucotóxica sobre células HL-60 também foi avaliada. A atividade leucotóxica foi determinada através do método de exclusão do azul de tripam. A deleção de 530 bp no promotor ltx foi avaliada usando-se o par de iniciadores PRO. A. actinomycetemcomitans foi detectado por cultura e por PCR. Por cultura, A. actinomycetemcomitans foi detectado em nove pacientes com periodontite (18 por cento) e em um indivíduo sadio (2 por cento). Por PCR esse microrganismo foi detectado em 44 por cento dos pacientes com periodontite e em 16 por cento dos saudáveis. Verificou-se diferença estatística entre a detecção do promotor do operon ltx, por PCR, diretamente do biofilme subgengival e do DNA bacteriano. Somente uma amostra clínica apresentou A. actinomycetemcomitans altamente leukotóxico. O biótipo II foi o mais prevalente e não foi observada correlação biótipo-atividade leucotóxica. A expressão da leucotoxina por A. actinomycetemcomitans na doença periodontal e outras doenças infecciosas necessita ser avaliado.