Development of Rat Caries-Induced Pulpitis Model for Vital Pulp Therapy.

Rodent animal models for vital pulp therapy are commonly used in dental research because their tooth anatomy and cellular processes are similar to the anatomy and processes in humans. However, most studies have been conducted using uninfected sound teeth, which makes it difficult to adequately assess the inflammatory shift after vital pulp therapy. In the present study, we aimed to establish a caries-induced pulpitis model based on the conventional rat caries model and then evaluate inflammatory changes during the wound-healing process after pulp capping in a model of reversible pulpitis induced by carious infection. To establish the caries-induced pulpitis model, the pulpal inflammatory status was investigated at different stages of caries progression by immunostaining targeted to specific inflammatory biomarkers. Immunohistochemical staining revealed that both Toll-like receptor 2 and proliferating cell nuclear antigen were expressed in moderate and severe caries-stimulated pulp, indicating that an immune reaction occurred at both stages of caries progression. M2 macrophages were predominant in moderate caries-stimulated pulp, whereas M1 macrophages were predominant in the severe caries-stimulated pulp. Pulp capping in teeth with moderate caries (i.e., teeth with reversible pulpitis) led to complete tertiary dentin formation within 28 d after treatment. Impaired wound healing was observed in teeth with severe caries (i.e., teeth with irreversible pulpitis). During the wound-healing process in reversible pulpitis after pulp capping, M2 macrophages were predominant at all time points; their proliferative capacity was upregulated in the early stage of wound healing compared with healthy pulp. In conclusion, we successfully established a caries-induced pulpitis model for studies of vital pulp therapy. M2 macrophages have an important role in the early stages of the wound-healing process in reversible pulpitis.

Influence of Pregnancy on the Inflammatory Process Following Direct Pulp Capping: a Preliminary Study in Rats.

The purpose of this study was to evaluate the inflammatory process following direct pulp capping during pregnancy. This experimental study involved 48 maxillary first molars of female Wistar rats. The procedures were performed in pregnant and non-pregnant animals (n =20 each). Direct pulp capping with mineral trioxide aggregate (MTA) and restoration with a light-cured resin composite was performed in half of exposed pulp specimens. In the other half of specimens, light-cured composite was placed directly on the exposed pulp. In the control groups (n=4 each), no intervention was performed. Animals were euthanized at 3 and 7 days. All sections (three per slide) were viewed under an optical microscope. One previously calibrated pathologist performed descriptive analysis and assigned scores for inflammatory response and tissue organization adjacent to the pulp exposure. The Kappa value for intra-examiner variability was 0.91. At 3 days, in animals treated with MTA, inflammatory infiltrate was absent in non-pregnant animals while mild inflammatory infiltrate was observed in some pregnant animals. The inflammatory response ranged from mild to severe in both groups treated with composite alone. At 7 days, the inflammatory response was more intense in pregnant than in non-pregnant animals treated with MTA; while this difference were not evident in animals treated with composite alone. In conclusion, pregnancy may not influence the inflammatory process following direct pulp capping with light-cured resin composite, which was always harmful to the pulp; while the tissue response after the direct pulp with MTA were more favorable in non-pregnant animals.

Influence of pregnancy on the inflammatory process following direct pulp capping: a preliminary study in rats

Abstract The purpose of this study was to evaluate the inflammatory process following direct pulp capping during pregnancy. This experimental study involved 48 maxillary first molars of female Wistar rats. The procedures were performed in pregnant and non-pregnant animals (n =20 each). Direct pulp capping with mineral trioxide aggregate (MTA) and restoration with a light-cured resin composite was performed in half of exposed pulp specimens. In the other half of specimens, light-cured composite was placed directly on the exposed pulp. In the control groups (n=4 each), no intervention was performed. Animals were euthanized at 3 and 7 days. All sections (three per slide) were viewed under an optical microscope. One previously calibrated pathologist performed descriptive analysis and assigned scores for inflammatory response and tissue organization adjacent to the pulp exposure. The Kappa value for intra-examiner variability was 0.91. At 3 days, in animals treated with MTA, inflammatory infiltrate was absent in non-pregnant animals while mild inflammatory infiltrate was observed in some pregnant animals. The inflammatory response ranged from mild to severe in both groups treated with composite alone. At 7 days, the inflammatory response was more intense in pregnant than in non-pregnant animals treated with MTA; while this difference were not evident in animals treated with composite alone. In conclusion, pregnancy may not influence the inflammatory process following direct pulp capping with light-cured resin composite, which was always harmful to the pulp; while the tissue response after the direct pulp with MTA were more favorable in non-pregnant animals.

Resumo O objetivo deste estudo foi avaliar o processo inflamatório do tecido pulpar após o capeamento pulpar direto, realizado durante a gestação. Este estudo experimental envolveu 48 primeiros molares superiores de ratos Wistar fêmeas. Os procedimentos foram realizados em animais prenhes e não prenhes (n=20). Após as exposições pulpares, o capeamento pulpar direto foi efetuado com agregado trióxido mineral (MTA) ou restauração direta com resina composta. Nos grupos controle (n=4), nenhuma intervenção foi realizada. Os animais foram submetidos à eutanásia após 3 e 7 dias. Todos os cortes foram avaliados através de um microscópio ótico. Um patologista previamente calibrado realizou analise histológica descritiva e estabeleceu escores para intensidade da resposta inflamatória e para o grau de organização tecidual na região adjacente à exposição pulpar. O valor de Kappa intra-examinador foi 0,91. No período experimental de 3 dias, nos animais tratados com MTA, o infiltrado inflamatório estava ausente nos não prenhes, enquanto infiltrado inflamatório moderado estava presente nos animais prenhes. A resposta inflamatória variou de moderada a severa em ambos os grupos tratados apenas com resina composta. Após o periodo experimental de 7 dias, a resposta inflamatória foi mais intensa nos animais prenhes que nos não prenhes do grupo do MTA, enquanto esta diferença não foi tão evidente nos animais que receberam capeamento pulpar direto com resina composta. Pode-se concluir, que a gestação pode não exercer influência no processo inflamatório do tecido pulpar após proteção pulpar direta com resina composta; a qual foi sempre danosa aos tecidos pulpares. No entanto, a resposta tecidual ao capeamento pulpar com MTA foi mais favorável nos animais não prenhes.

Influence of preoperative pain in the success rate of indirect pulp capping: a retrospective study.

BACKGROUND: The association of preoperative pain and indirect pulp treatment in permanent teeth is still unknown. This study aimed to evaluate the influence of preoperative pain in the success rate of indirect pulp capping. METHODS: The sample of this retrospective study was constituted for 133 teeth treated in a Private clinic in Joinvile, Brazil, by one experienced dentist between 2007 and 2012. Data related to clinical and demographic variables that could influence in the success rate of indirect pulp capping were also collected, such patient age and sex, type of teeth and arch. Chi­square test was used to evaluate the association between preoperative pain with postoperative one and success of the treatment. Logistic regression was performed to identify significant clinical and demographical factors associated with the success of the indirect pulp capping. RESULTS: The overall success rate was 100% in the absence of preoperative pain. However, when the preoperative pain was present, the failure rate was 18.3%. Statistical analysis showed significant association between preoperative pain and postoperative one and failure rate of the indirect pulp capping. The other independent variables were not associated with the success rate of the treatment. CONCLUSIONS: The presence of preoperative pain is associated with the decrease of the success rate of indirect pulp capping.

One-step partial or complete caries removal and bonding with antibacterial or traditional self-etch adhesives: study protocol for a randomized controlled trial.

BACKGROUND: Current concepts in conservative dentistry advocate minimally invasive dentistry and pulp vitality preservation. Moreover, complete removal of carious dentin in deep carious lesions often leads to pulp exposure and root canal treatment, despite the absence of irreversible pulp inflammation. For years, partial caries removal has been performed on primary teeth, but little evidence supports its effectiveness for permanent teeth. Furthermore, the recent development of new antibacterial adhesive systems could be interesting in the treatment of such lesions. The objectives of this study are to compare the effectiveness of partial versus complete carious dentin removal in deep lesions (primary objective) and the use of an antibacterial versus a traditional two-step self-etch adhesive system (main secondary objective). METHODS/DESIGN: The DEep CAries Treatment (DECAT) study protocol is a multicenter, randomized, controlled superiority trial comparing partial versus complete caries removal followed by adhesive restoration. The minimum sample size required is 464 patients. Two successive randomizations will be performed (allocation ratio 1:1): the first for the type of excavation (partial versus complete) and the second (if no root canal treatment is required) for the type of adhesive (antibacterial versus traditional). For the two objectives, the outcome is the success of the treatment after 1 year, measured according to a composite outcome of five FDI criteria: material fracture and retention, marginal adaptation, radiographic examination (including apical pathologies), postoperative sensitivity and tooth vitality, and carious lesion recurrence. DISCUSSION: The study will investigate the interest of a conservative approach for the management of deep carious lesions in terms of dentin excavation and bioactive adhesive systems. The results may help practitioners achieve the most efficient restorative procedure to maintain pulp vitality and increase the restoration longevity. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02286388 . Registered in November 2014.

A histologic assessment of a HYBENX® oral tissue decontaminant in vital pulp therapy in dogs.

The aim of this study was to assess HYBENX® Oral Tissue Decontaminant (HOTD) in treating vital pulp exposure in a canine model. The use of HOTD solution was compared to an accepted and standard regimen for vital pulp exposure, an application of a commercial calcium hydroxide product (Ca(OH)2). Both control and experimental treatments were followed by restoration with a commercial zinc oxide and eugenol obtundant intermediate restorative material and thermal insulator (ZOE). At 7 days there was 100% pulp vitality with HOTD and 50% with Ca(OH)2. New dentin formation was seen in 62.5% of the HOTD treated pulps and none of the Ca(OH)2 treatment group. The vital pulp exposures at day 21 post treatment with HOTD also showed significant improvement over Ca(OH)2 in the presence of odontoblasts, new dentin formation and pulp survivability. The presence of odontoblasts and new dentin was noted in 71% of the HOTD cases versus 50% of the survivable Ca(OH)2 cases. Furthermore, 100% of HOTD cases had vital pulps versus 62.5% of Ca(OH)2 cases. The 60-day specimens of both experimental and control techniques exhibited histologically similar appearances and were similar in outcomes. HOTD treatment at day 7 showed a significant positive difference, both in the formation of new dentin and tooth vitality. HOTD proved better for the post 21-day specimens and equivalent for the 60-day pulp specimens with no evidence of untoward tissue reactions or results.

In vitro cytotoxicity evaluation of different pulp capping materials: a comparative study.

Direct pulp capping covers the exposed surface of the pulp to maintain its vitality and preserve its functional and biologic activity. The aim of the present study was to compare the biocompatibility effects of seven different pulp-capping materials in vitro: Dycal®, Calcicur®, Calcimol LC®, TheraCal LC®, ProRoot MTA®, MTA-Angelus®, and Biodentine®. Using the Transwell insert methodology by Alamar blue test, we evaluated the cytocompatibility of the above mentioned materials towards murine odontoblasts cells (MDPC-23) at three different times (24, 48, and 72 h). For additional control, the cell viability at 72 hours was also assessed by MTT assay. Morphological analysis of murine odontoblasts was assessed by Confocal Laser Scanning Microscope. The results indicate significantly different biocompatibility among materials with different composition. Biodentine® and mineral trioxide aggregate (MTA)-based products showed lower cytotoxicity, varying from calcium hydroxide-based materials, which exhibited higher cytotoxicity. Although our findings are limited to in vitro conditions, the observation that Biodentine® caused a cytotoxic effect similar to MTA suggests that it may be considered an alternative in pulp-capping treatment, as calcium hydroxide-based materials present higher cytotoxic effects.

Comparative Study of Pulpal Responses to Pulpotomy with ProRoot MTA, RetroMTA, and TheraCal in Dogs' Teeth.

INTRODUCTION: This study was conducted to evaluate and compare pulpal responses to ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK), RetroMTA (Meta Biomed Co, Ltd, Seoul, Korea), and TheraCal (Bisco Inc, Schamburg, IL) in dog partial pulpotomy models. METHODS: Partial pulpotomies were performed on 60 beagle teeth. The exposed pulp tissues were randomly capped with either ProRoot MTA (n = 15), RetroMTA (n = 15), TheraCal (n = 15), or interim restorative material as a negative control (n = 15). After 4 weeks, the teeth were extracted and processed for histologic and immunohistochemical examinations using osteocalcin and dentin sialoprotein. Calcific barrier formation, inflammatory reaction, and the odontoblastic layer were evaluated and scored in a blind manner. The areas of newly formed calcific barriers were measured for each group. RESULTS: In most of the ProRoot MTA and RetroMTA specimens, continuous calcific barriers were formed, and the pulps contained palisading patterns in the odontoblastic layer that were free of inflammation. However, the TheraCal specimens had lower quality calcific barrier formation, extensive inflammation, and less favorable odontoblastic layer formation. Overall, areas of newly formed calcific barrier were higher in the ProRoot MTA and RetroMTA specimens than in the TheraCal specimens. Also, immunohistochemistry revealed that osteocalcin and dentin sialoprotein were more clearly visible in the ProRoot MTA and RetroMTA specimens than in the TheraCal specimens. CONCLUSIONS: RetroMTA could provide an alternative to ProRoot MTA. Both materials produced favorable pulpal responses that were similar in nature, whereas TheraCal produced less favorable pulpal responses.

Pulpo-dentin complex response after direct capping with self-etch adhesive systems.

The purpose of the present study was to evaluate morphologically the response of feline teeth pulp to direct pulp capping with two different self-etch adhesive systems. Twenty-four cavities in feline teeth were mechanically exposed and assigned to one of two experimental groups: AdheSE + Tetric Ceram (the ASE group), or Adper Prompt L-Pop + Filtek Supreme (the APLP group). There was also a control group Dycal Ca(OH)(2) liner + Amalgam (the CH group eight teeth), and six teeth were used as an intact control group. The animals were sacrificed after 40 days. The teeth were removed and processed for standard histological evaluation, using a scoring system for inflammatory cell response, pulp tissue disorganisation, reparative tissue formation, and the presence of bacteria. Statistical analysis revealed no significant differences between the ASE and APLP self-etching resin systems during the observation period. The majority of the specimens presented inflammatory pulp response with tissue disorganisation and a lack of dentinal bridge formation. CH capping resulted in a significantly smaller inflammatory pulp response and a considerably higher incidence of reparative dentin formation. ASE and APLP were comparably effective as direct pulp capping materials, but their application resulted in significantly greater pulp tissue damage than CH capping. Further in vivo human studies are necessary to determine which adhesive resin systems should be clinically used for direct pulp capping without incurring severe damage to the pulpal tissue.

Genotoxic effect of formocresol pulp therapy of deciduous teeth.

OBJECTIVE: To investigate whether formocresol, in Buckley's original formulation, used for pulp therapy of deciduous teeth, can have a genotoxic effect. Genotoxicity was tested in lymphocyte cultures from the peripheral blood of children aged 5-10y, in Recife, Pernambuco, Brazil. This was a case-control study. The sample comprised 40 children who had primary teeth with non-vital pulps. Two venous blood samples (6-8ml) were collected from each child, the first prior to pulp therapy (control group) and the second 24h after pulp therapy (experimental group). Lymphocyte cultures were grown in 78% RPMI 1640 medium, 20% fetal bovine serum, 2% phytohemagglutinin. The lymphocytes were assessed for chromosomal aberrations; each sample involved analysis of 100 metaphases. There was a statistically significant difference between the control and treated groups for the isochromatid gap (p<0.001), chromatid break (p<0.009), isochromatid break (p<0.046), other chromosomal alterations (p<0.001), and for total aberrations. In view of these results, caution in the use of formocresol in pediatric dentistry is recommended.

Cytotoxicity of mineral trioxide aggregate (MTA) and bone morphogenetic protein 2 (BMP-2) and response of rat pulp to MTA and BMP-2.

OBJECTIVE: The aim of this study was to assess the cytotoxicity of mineral trioxide aggregate (MTA) and bone morphogenetic protein 2 (BMP-2) and the response of rat pulp tissue to MTA and BMP-2. STUDY DESIGN: For cytotoxicity studies, 1 g MTA was mixed with or without 1 microg of BMP-2 and allowed to set for 1, 24, 48, or 72 hours before addition of samples to 2-mL aliquots of culture medium. The viability of MG-63 cells was determined using the dimethyl-thiazol-diphenyltetrazolium bromide (MTT) assay. For animal studies, upper first molars from 32 Sprague-Dawley rats were used, the molars were exposed, and 1 g MTA cement was placed in the first molars. In left molars, 1 microg BMP-2 was additionally placed on exposed pulps with MTA. After 2 weeks and 7 weeks, rats were killed and histologic sections assessed by light microscopy. RESULTS: In MTT assay, the viability was higher in the MTA with BMP-2 group than in the MTA-only group up to 24 hours, but was not significantly different thereafter. In animal study, inflammation was higher in the MTA-only group than in the MTA with BMP group, although this difference did not attain statistical significance. CONCLUSIONS: The addition of BMP-2 had a beneficial effect in vitro, reducing the initial cytotoxicity of freshly mixed MTA. However, the pulp reaction to a combination of MTA and BMP-2 was not significantly better than use of MTA alone.

Pulp response to resin-modified glass ionomer and calcium hydroxide cements in deep cavities: A quantitative systematic review.

OBJECTIVE: To quantitatively determine whether the pulp response to resin-modified glass ionomer cements placed in deep cavities differs from that generated by calcium hydroxide cement. SOURCES: Five databases were searched for articles up to 31 May 2009. INCLUSION CRITERIA: titles/abstracts relevant to topic; published in English; two-arm longitudinal in vivo trial; containing computable dichotomous datasets for test and control group. EXCLUSION CRITERIA: not all entered subjects accounted for at the end of the trial; subjects of both groups not followed up in the same way; trial on animal tissue. DATA: One randomized and five non-randomized control trials, reporting on 1 and 17 datasets, respectively, were accepted. From non-randomized trials, the Relative Risk with 95% Confidence Interval of 13 datasets showed no statistically significant differences (p>0.05) and 4 showed a statistically significant difference between both materials. Meta-analysis of datasets from these trials found no difference between the inflammatory cell response after 30 days (0.87; 95%CI 0.59-1.26; p=0.46); 38% less inflammatory cell response with calcium hydroxide after 60 days (0.62; 95%CI 0.50-0.76; p<0.00001); higher number of intact odontoblasts beneath restored cavities after 381 days (0.56; 95%CI 0.38-0.82; p=0.0008). The results from the randomized control trial (1.40; 95%CI 0.92-2.14; p=0.11) indicated no difference in clinically identifiable pulp symptoms after two years. All trials showed limited internal validity due to selection bias. CONCLUSION: No conclusive statement about the superiority of either type of material can yet be made. Further high-quality randomized control trials are needed.

The adverse effect of self-etching adhesive systems on dental pulp after direct pulp capping.

OBJECTIVES: To evaluate the histopathological changes in mechanically exposed dog pulps capped with three self-etching adhesive systems. MATERIAL AND METHODS: Seventy-two Class V cavities were prepared under rubber dam isolation in dogs. The pulps were exposed and capped with Clearfil SE Bond (Kuraray), Imperva FluoroBond (Shofu), Prompt L-Pop (3M ESPE), and Dycal (Dentsply; control capping agent), respectively. Histopathological examination of the teeth was performed at 7, 14, and 30 days postoperatively. Hematoxylin-eosin staining was performed to assess the inflammatory cell response, tissue disorganization, and hard tissue formation. Brown and Brenn staining was used to detect the presence of bacteria. The data were analyzed by Kruskal-Wallis and Nemenyi tests. RESULTS: Most pulps showed moderate to severe inflammatory responses. Hard tissue formation appeared at 14 to 30 days. Positive bacterial staining was observed in most specimens in experimental groups. The histological changes in the pulps of the experimental groups were more pronounced than in the control group. Differences in inflammatory response, tissue disorganization, and hard tissue formation were observed among teeth treated with the three self-etching systems. CONCLUSION: Microleakage has a critical influence on pulpal repair. It is not beneficial to cap the pulp with self-etching adhesive systems. Diverse pulpal responses were observed to the self-etching adhesive systems, and the histological changes were more pronounced than in the control pulps treated with Dycal. The effects of the self-etching adhesive systems are such that these materials require further study to address issues of bacterial microleakage during placement of restorations.

[Response of dental pulp to self-etching adhesive systems used in indirect capping. A literature review]. / Reakcja miazgi zebów na samowytrawiajace systemy Laczace stosowane w metodzie pokrycia posredniego. Przeglad pismiennictwa.

OBJECTIVE: To review the literature on dental pulp responses to self-etching adhesive systems used in indirect capping. MATERIAL AND METHODS: Many studies in vitro and in vivo focused on biocompatibility of the self-etching adhesive system used in deep defects. Clinical and radiographic findings from animal and human studies are compared and discussed. RESULTS: Self-etching adhesive systems may be useful when applied to dentin. The results in animal studies cannot be extrapolated directly to humans. Many studies in vitro have shown that components of self-etching adhesive systems exhibit cytotoxic effects in contact with cell cultures. CONCLUSIONS: The reaction of dental pulp to self-etching bonding agents depends on the depth of defect, type of agent, and method of application.

Radiographic evaluation of pulpal and periapical response of dogs' teeth after pulpotomy and use of recombinant human bone morphogenetic protein-7 as a capping agent.

PURPOSE: The purpose of this study was to evaluate radiographically the pulpal and periapical response of dogs' teeth after pulpotomy and the use of recombinant human bone morphogenetic protein-7 (rHuBMP-7). METHODS: Pulpotomies were performed in 60 teeth of 6 dogs, and the remaining radicular pulp tissue was capped with the following materials: (a) groups 1 and 5-recombinant human bone morphogenetic protein-7 associated with recombinant human-like collagen; (b) groups 2 and 6-recombinant human-like collagen; (c) groups 3 and 7-calcium hydroxide; and (d) groups 4 and 8-zinc oxide and eugenol cement. After 7 days (groups 1-4) and 70 days (groups 5-8), standardized periapical radiographs were taken and the integrity of the lamina dura, presence of areas of periapical bone rarefaction, internal/external root resorption, and dentin bridge formation were evaluated. The results were analyzed statistically by Fisher's exact test and Bonferroni correction. The radiolucent areas suggestive of periapical lesions associated with the roots were measured in mm2, and the results were compared by Kruskal-Wallis test. RESULTS: In the 7-day period, all specimens in groups 1 to 4 presented intact lamina dura and absence of periapical bone rarefaction, internal/external root resorption or dentin bridge formation. In the 70-day period, no specimen in groups 5, 6, and 8 presented dentin bridge formation. Periapical bone rarefaction areas were observed to be associated with 100%, 60%, and 40% of the roots in group 6, 8, and 5, respectively. The largest lesions were found in group 6, followed by groups 5 and 8 (P<.05). In group 7, there was dentin bridge formation in 60% of the cases and intact lamina dura and no periapical bone rarefaction in all specimens. CONCLUSION: The use of rHuBMP-7/rHuCollagen as a capping material after pulpotomy did not induce mineralized tissue deposition, leading to the formation of radiographically visible periapical lesions.

Evaluation of mineral trioxide aggregate and calcium hydroxide cement as pulp-capping agents in human teeth.

This study evaluated the histomorphologic response of human dental pulps capped with mineral trioxide aggregate (MTA) and Ca(OH)2 cement (CH). Pulp exposures were performed on the occlusal floor of 40 human permanent premolars. After that, the pulp was capped either with CH or MTA and restored with composite resin. After 30 and 60 days, teeth were extracted and processed for histologic exam and categorized in a histologic score system. The data were subjected to Kruskal-Wallis and Conover tests (alpha = .05). All groups performed well in terms of hard tissue bridge formation, inflammatory response, and other pulpal findings. However, a lower response of CH30 was observed for the dentin bridge formation, when compared with MTA30 and MTA60 groups. Although the pulp healing with calcium hydroxide was slower than that of MTA, both materials were successful for pulp capping in human teeth.

Deep caries lesions after incomplete dentine caries removal: 40-month follow-up study.

Radiographic changes after indirect pulp capping (32 teeth in 27 patients) were studied for up to 36-45 months. Radiolucent zone (RZ) depth and tertiary dentine formation were assessed qualitatively and changes in radiographic density (by image subtraction) in RZ and control areas (CA) were estimated. During follow-up there were 1 pulp necrosis, 1 pulp exposure, 3 fractures and 3 withdrawals. Twelve cases showed decreased RZ depth and 4 displayed tertiary dentine. No changes with time in density of CA or RZ, or in the difference between them, were observed. It is concluded that indirect pulp capping arrests lesion progression, suggesting that complete dentine caries removal is not essential for caries control.

The incidence of pulp healing defects with direct capping materials.

PURPOSE: To (1) study the injury and healing activity of the pulp tissue to calcium hydroxide [Ca(OH)2], resin composite (RC) and resin-modified glass-ionomer (RMGI) materials when used as direct pulp capping agents, and (2) compare the incidence of healing defects between these materials. METHODS: 135 Class V pulp exposed cavities were prepared in non-human primate teeth. Direct pulp capping was conducted over 6 to 730 days with hard set Ca(OH)2, RMGI and CR materials. Healing defects recorded were: (1) bacterial leakage with McKays stain; (2) operative debris including dentin fragments and particles of capping material; (3) pulpal inflammatory activity according to FDI standards; (4) area and absence of dentin bridge formation; and (5) presence of tunnel defects in bridge. Statistical analysis was evaluated using ANOVA. RESULTS: The capping materials were associated with varying levels of pulp healing defects, including tunnel defects (P= 0.0001); operative debris (P= 0.0001); pulpal inflammatory cell activity (P= 0.0073) and bacterial leakage (P= 0.0260). Other healing defects, and the area of dentin bridge were not influenced by capping materials (P> 0.05).

Biological effects of flowable resin composite on erythrocytes and lymphocytes using an in vitro model.

AIM: The purpose of the study was to evaluate the biological effects of a flowable resin composite on erythrocytes and rat spleen lymphocytes (RSL) using an in vitro model. METHODOLOGY: Rat spleen lymphocytes were placed into microcentrifuge tubes as a pulp model. An artificial pulp exposure was made through the top of the microcentrifuge tube with a 16G needle. The exposure site was filled with a flowable resin composite and photo-polymerized, and the other specimens were not polymerized. The survival rates were determined by a haemocytometer. Red blood cell (RBC) suspension (0.5%) was reacted with the flowable resin composite. The haemolytic activity was evaluated at room temperature (20 degrees C) using a supernatant of each sample by measuring 545 nm of absorbency with a spectrophotometer. To evaluate the effect of flowable resin composite on RBCs, supernatant and precipitated samples were analysed by sodium dodecyl sulphate-polyacrylamide gel (SDS-PAGE). RESULTS: The cell survival rate of the polymerized group was significantly lower compared with that of the nonpolymerized group at the same areas (P < 0.05). The values of haemolysis (absorbency) were 2.16 for the polymerized group, 2.14 for the nonpolymerized group, and 2.18 for the control group (saline). There were no significant differences among them (P > 0.05). The protein component in the supernatant and precipitate exhibited the same reaction with flowable resin composite regardless of the completion of the polymerization, resulting in no change of protein band mobility on SDS-PAGE. CONCLUSIONS: The degree of haemolysis was not influenced by the completion of polymerization. The flowable resin composite tested provoked an adverse effect on lymphocytes when it was not polymerized and the degree of haemolysis was not affected by the status of the polymerization.

Adhesive resin and the hydrophilic monomer HEMA induce VEGF expression on dental pulp cells and macrophages.

Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis by inducing endothelial cell proliferation, migration and survival. Direct pulp capping with an adhesive resin system was shown to induce local increase in blood vessel density and lack of dentin bridging. However, the mechanisms involved in the increase in blood vessel density observed near the pulp exposures capped with an adhesive resin are largely unknown. OBJECTIVES.: To investigate the effect of an adhesive resin or one of its hydrophilic monomers (HEMA), in the expression of VEGF by pulp cells. METHODS.: Mouse odontoblast-like cells (MDPC-23), undifferentiated pulp cells (OD-21), gingival fibroblasts, and macrophages were exposed to SingleBond (3M) or to 0-1000nM HEMA. VEGF expression was evaluated by ELISA and semi-quantitative RT-PCR. RESULTS AND SIGNIFICANCE.: VEGF expression was upregulated in MDPC-23 cells exposed to HEMA (p<0.001) or to SingleBond (p<0.018), and in macrophages exposed to HEMA (p<0.001) or SingleBond (p=0.001). In contrast, VEGF expression remained unchanged in undifferentiated pulp cells (OD-21), or fibroblasts exposed to either HEMA or Single Bond (p>0.05). Treatment with SingleBond or HEMA did not affect VEGF expression at the mRNA level of any cell type evaluated here, suggesting that the induction of VEGF expression in these cells is regulated primarily at the post-transcriptional level. These findings suggest that VEGF is involved in the regulation of pulp neovascularization observed in response to the application of adhesive resins at site of pulp exposure.