Pulpal Reactions Research Articles

Pulpal Disease Arising from Medication-related Osteonecrosis of the Jaw: A Case Report

Although bisphosphonates are widely used to treat conditions such as osteoporosis, they may cause osteonecrosis of the jaw. We treated a patient with no history of tooth extraction or other surgical treatment who developed medication-related osteonecrosis of the jaw (MRONJ) with secondary pulpal disease. A 79-year-old woman presented with purulent discharge from the gum at the incisor region. She had been using bisphosphonates for 9 years. Tooth #6 had undertaken root canal treatment at a general practice. All teeth other than tooth #6 reacted to electric pulp testing. Computed tomographic imaging revealed signs suggestive of necrotic bone, and MRONJ was diagnosed. Teeth #7 and #8, which had initially exhibited vital reactions, also subsequently ceased to react to thermal and electric pulp testing. Root canal treatment was performed on teeth #6–8, and their condition was monitored. Computed tomographic imaging at 9 months after the first presentation revealed that the bone defect had greatly enlarged with separation of the necrotic bone; therefore, excision of the necrotic bone and curettage were performed in the department of oral and maxillofacial surgery. The loss of pulp reaction in teeth that had exhibited a vital reaction at the first presentation was considered to indicate that teeth #6–8 had developed dental pulp pathosis as a result of MRONJ.

Resinous adhesive systems differentially affect the expression of cytokines by human monocytes stimulated or not with Streptococcus mutans in vitro

ObjectivesThe polymerization of adhesive systems is incomplete and the residual monomers that have been released have a cytotoxic capacity. Some teeth develop into pulp necrosis after composite resin restorations. Considering frequent pulpal inflammation in response to cariogenic bacteria, substances released from the patches could affect the cells of the inflammatory infiltrate and interfere with the mechanisms of defense against microorganisms and protection of pulpal tissue. The aim of this study was to evaluate the effect of substances released by different resinous adhesive systems on cell viability and cytokine expression by human monocytes stimulated in vitro with Streptococcus mutans. DesignPeripheral blood mononuclear cells from 10 healthy subjects were stimulated with S. mutans and then incubated with supernatants obtained from the Single Bond Universal (SBU) or Clearfil SE Bond (CSEB) adhesive systems for eight hours. Staining with Annexin V and 7AAD for analysis of apoptosis were performed and detection of monocytes expressing cytokines IL-1α, IL-6, IL-8, IL-10, IL-12 and TNF-α were performed by flow cytometry. ResultsNo treatment significantly affected apoptosis in monocytes. SBU supernatant increased the frequency of monocytes expressing IL-8 and decreased the monocytes expressing IL-10. Considering S. mutans-stimulated cells, while SBU increased the frequency of IL-8+ monocytes, CSEB reduced the frequency of IL-6 and TNF-α positive monocytes. ConclusionsProducts released from SBU seem to induce proinflammatory effects on monocytes while those from CSEB show an anti-inflammatory outcome. These effects may interfere in the control of cytokine-mediated immunoinflammatory pulp reactions, both in the presence and absence of stimulation by cariogenic bacteria.

Immediate response of human dental pulp capped with mineral trioxide aggregate, Portland cement and biodentin

Background: The initial inflammatory reaction of pulp capping materials on the dental pulp has an intimate relation in promoting the future cellular differentiation and biomaterial mineralisation. So, analysis of immediate pulpal tissue reaction in vivo, is also important for evaluation of ultimate efficacy any pulp capping agent. To observe immediate inflammatory response of Human Dental Pulp capped with Mineral Trioxide Aggregate (MTA), Biodentin and Portland Cement (PC).
 Methods: A total of 70 permanent premolars teeth planned to be extracted for orthodontic alignment of occlusion were used as study sample. The teeth were divided into 3 experimental groups, MTA (n=20), Biodentin (n=20) Portland cement (n=20) and control group (n=10). After having an occlusal exposure of approximately 1.5 mm in diameter; in group A, pulp of teeth was capped with 2-mm-thick layer of ProRoot White MTA (Dentsply) and in group B, with sterile Biodentin (Septodont) according to the manufacturer’s recommendations. Whereas in group C, pulp of teeth was capped with sterile Portland Cement (PC). After placing the experimental material in each group, all teeth restored with glass i‹xiomer cement. After 24 hours the teeth were extracted, fixed in 10% buffered formalin solution, then decalcified by 10% nitric acid and embedded in paraffin. Finally, sectioned into 2 to 3-micron-thick serial sections in the linguo-buccal plane and stained with hematoxylin-eosin. After then the amount of pulp inflammation (type, intensity, and extension) were determined by using a predetermined evaluation criterion under an optical microscope at 40a magnification. Ten intact teeth, which received no exposure and pulp capping but extracted due to orthodontic purpose were also collected and treated as the control group (group D); undergone same histologic preparation and evaluation. Significantstatistical differences among the experimental groups were to be found (p<0.05).
 Results: Histologically, all the three tested materials produced immediate pulpal tissue reaction. ‘Biodentin’ found to be most immediate pulpal tissue reactive (reactive in 100% cases) and ‘Portland Cement’ showed least immediate tissue reaction (only in 30.0% cases). whereas, MTA produced immediate tissue reaction only in 50.0% cases. Immediate pulpal inflammatory reaction in response to tested material found to be statistically significant different between ‘Biodentin’ and ‘Portland cmient’ (p=0.01), also between ‘Biodentin’ and ‘MTA’ and (p=0.001); but there was no statistically significant difference between ‘MTA’ and ‘Portland cement’ (p =0.197).
 Conclusion: Considering the maximum immediate pulpal tissue reaction (Inflammation), Biodentin is expected to produce most favorable ultimate bioactivity (biomaterial mineralization) after pulp capping.
 Bangladesh Med Res Counc Bull 2019; 45: 108-116

Dentin-pulp complex reactions in conventional and radiation-related caries: A comparative study.

BackgroundRadiation-related caries (RRC) is one of the most significant oral toxicities of head and neck radiotherapy (HNRT); however, the potential of radiation to directly cause harmful dentin and pulpal effects and impair response to caries progression is controversial.Material and MethodsTherefore, the aim of this study was to characterize the reactions of the dentin-pulp complex in teeth affected by RRC. Patients and methods: Twenty-two carious teeth extracted from 22 head and neck cancer (HNC) patients were divided into control (conventional caries; n=11) and irradiated (RRC; n=11) groups and paired matched by dental homology, clinical patterns of caries progression following the Post-Radiation Dental Index (PRDI) and microscopic depth of carious invasion. Histopathological characteristics based on morphological hierarchy, cell populations of dental pulp, blood vessels, neural elements, extracellular matrix components, inflammation, patterns of carious invasion and reactionary dentin presence were evaluated by optical light microscopy and histomorphometry.ResultsMean PRDI scores were 3.2 for the control group and 3.8 for the irradiated group. Dentin demineralization patterns were also similar between the groups and the mean depths of demineralization were 1,158.58µm and 1,056.89µm for the control and irradiated groups, respectively.ConclusionsPulp histopathological changes and dentin reaction patterns were similar between groups and varied according to the PRDI scores and carious lesions depth. Dentin and pulp reactions are highly preserved in RRC teeth. Key words:Cancer, radiotherapy, radiation-related caries, teeth, pulp.

Histological response in dental pulp of accelerate tooth movement using periodontal ligament distraction osteogenesis in dogs

PurposeThis study compared initial histological change in dental pulp in response to periodontal ligament distraction osteogenesis (PLDO) with that to conventional orthodontic treatment to determine the effectiveness of PLDO. Materials and methodsPLDO was performed on the right side (PLDO group) and conventional orthodontic treatment on the left side (CCS group) in 6 male beagle dogs. Untreated teeth served as a control group. Radiographs were obtained after appliance activation. Change in pulpal blood flow was measured using a Doppler blood flow meter. The sections were stained with hematoxylin-eosin and Masson’s trichrome for morphological observation. Cell response was observed by immunohistochemistry using proliferating cell nuclear antigen (PCNA) and the TUNEL method. ResultsThe total movement distance of the premolar was significantly greater in the PLDO group than in the CCS group. A decrease in pulpal blood flow and the number of odontoblast cells was observed together with dental pulp capillary dilation at 5 and 12 days after appliance attachment in both groups. While many TUNEL-positive cells were observed on the 5th day in both experimental groups, they showed a decrease at 12 days. More PCNA-positive cells were observed on the 12th day than on the 5th day in both groups. There was no difference in invasiveness between the pulpal reaction to PLDO and that to conventional orthodontic treatment, suggesting that the level of recovery is similar. ConclusionPLDO enabled rapid tooth movement and initial histological change in the dental pulp was similar to that in response to conventional orthodontic treatment.

Histopathological Evaluation of Dental Pulp of Primary Teeth Pulpotomized with Formocresol with/without a Capping Agent: A Randomized Clinical Trial.

Objectives:This study aimed to assess the reaction of dental pulp of pulpotomized teeth with/without applying a capping agent. This study was performed as randomized clinical trial.Materials and Methods:This split-mouth clinical trial was conducted on eight pairs of primary canine teeth scheduled for extraction as part of orthodontic treatment. The teeth were randomly assigned to the intervention and control groups. In the intervention group, canine teeth were restored with amalgam after pulpotomy with formocresol. In the control group, zinc oxide eugenol paste was applied as the capping agent after pulpotomy with formocresol, and the teeth were then restored with amalgam. After 1 month, the teeth were extracted in both groups and stained with hematoxylin and eosin for histological analysis. Pulp reaction was assessed in terms of pathological parameters. Data were analyzed using the Mann–Whitney U-test and Fisher's exact test. The statistical analysis software was SPSS 16.Results:No significant difference was found between the two groups in terms of inflammation, vitality, internal resorption, bleeding, presence of osteoclasts and dentinoclasts, and internal regeneration. Dentinal bridge did not form in any group.Conclusion:According to the results of this study, formocresol pulpotomy of primary teeth can be completed without the application of a capping agent.

Evaluation of the effect of adding micro-hydroxyapatite and nano-hydroxyapatite on the microleakage of conventional and resin-modified Glass-ionomer Cl V restorations.

BackgroundPulpal reaction to restorative materials depends on marginal microleakage, which is a dynamic phenomenon that allows bacteria and fluids to traverse across the tooth-restoration interface. Glass-ionomer cement (GIC) exhibits low microleakage due to direct bonding to tooth structures. Hydroxyapatite (HAP) based on the similarity with tooth structure may decrease the microleakage. The aim of this in vitro study was to evaluate marginal microleakage of a mixture of conventional and resin-modified glass-ionomer (RMGI) with micro- and nano-HAP.Material and MethodsIn this in vitro study, 30 non-carious extracted human third molar teeth were used. Standard Cl V cavities were prepared on the buccal and lingual surfaces. The cavities were restored in six experimental groups as follows: group 1, conventional glass-ionomer cement (CGIC); group 2, CGIC with micro-HAP; group 3, CGIC with nano-HAP; group 4, RMGI; group 5, RMGI with micro-HAP; group 6, RMGI with nano-HAP. The restorations were finished and polished. The teeth were coated with nail polish, sealed with sticky wax, thermocycled and placed in a solution of 2% basic fuchsine for 24 hours. The teeth were sectioned and microleakage was measured. Kruskal-Wallis, Man-Whitney and Wilcoxon tests were used for data analysis (P<0.05).ResultsThe data analysis revealed significantly lower microleakage in groups 5 and 6 at both occlusal and gingival margins. Also in these two groups the gingival microleakage was significantly lower than occlusal margin (P=0.009 and P=0.001 respectively), but in groups 1(CGIC) and 3(CGIC+ nano-HAP) and 4(RMGI) the microleakage of occlusal margin were significantly lower than that of gingival margin (P=0.001, P=0.007 and P=0.001 respectively).ConclusionsMixing RMGI with nano-HAP and micro-HAP resulted in lower microleakage. Key words:Glass-ionomer, micro-hydroxyapatite, microleakage, nano-hydroxyapatite.

A cytotoxic evaluation of 7 th generation dentin bonding agent on human pulp cells

Dentin bonding agents are resin based materials that used in clinical dentistry inorder to prevent leakage and promote adherent of filling material to the enamel anddentin. However, the polymerization of dentin bonding agents will release residualmonomer that may interact with pulp tissue. This in vitro study is aimed to evaluatethe cytotoxicity of new 7thgeneration dentin bonding agents (G Bond) on stem cellsfrom human exfoliated deciduous teeth (SHEDs). The proliferated human pulp cellswere incubated at 37 C for 48 hours. Under aseptic conditions, extracted testspecimen were plated in 96 well of tissue tray. SHEDs were placed on each well withdifferent concentration of dentin bonding agents, and then incubated at 37 C for 72hours exposure. The cytotoxic effect was recorded by using MTT assay method.Statistical analysis showed that higher concentration of dentin bonding agents (IC=0.035 mg/ml)exerts higher toxic effect to the human pulp cells (SHEDs). This studyconcluded that pulpal reaction to dentin bonding agent may depend on number ofapplication procedure.

Hypoplasia Management in permanent incisor caused by primary incisor intrusion- A case report

Abstract Orofacial trauma is a serious orodental and general health problem that may have medical, esthetic and psychological consequences for children and their parents. When the root of the primary tooth is close to the unerupted permanent tooth, primary tooth trauma may result in developmental disturbances and pulpal reaction in that permanent tooth. We report a case in which injury to the primary dentition resulted in developmental disturbances in the underlying permanent tooth. Localized malformation of the crown and enamel hypoplasia was treated with a light-cured composite resin restoration. How to cite this article Neena IE, Ananthraj A, Praveen P. Hypoplasia management in permanent incisor caused by primary incisor intrusion –A case report. CODS J Dent 2015;7:50-51

Immediate human pulp response to ethanol-wet bonding technique

ObjectivesTo evaluate the short-term response of human pulps to ethanol-wet bonding technique. MethodsDeep class V cavities were prepared on 17 sound premolars and divided into three groups. After acid-etching, the cavities from groups 1 (G1) and 2 (G2) were filled with 100% ethanol or distilled water, respectively, for 60 s before the application of Single Bond 2. In group 3 (G3, control), the cavity floor was lined with calcium hydroxide before etching and bonding. All cavities were restored with resin composite. Two teeth were used as intact control. The teeth were extracted 48h after the clinical procedures. From each tooth serial sections were obtained and stained with haematoxylin and eosin (H/E) and Masson's trichrome. Bacteria microleakage was assessed using Brown & Brenn. All sections were blindly evaluated for five histological features. ResultsMean remaining dentine thickness was 463±65μm (G1); 425±184μm (G2); and 348±194μm (G3). Similar pulp reactions followed ethanol- or water-wet bonding techniques. Slight inflammatory responses and disruption of the odontoblast layer related to the cavity floor were seen in all groups. Stained bacteria were not detected in any cavities. Normal pulp tissue was observed in G3 except for one case. ConclusionsAfter 48h, ethanol-wet bonding does not increase pulpal damage compared to water-wet bonding technique. Clinical significanceEthanol-wet bonding may increase resin-dentine bond durability. This study reported the in vivo response of human pulp tissue when 100% ethanol was applied previously to an etch-and-rinse simplified adhesive system.

Histological effects of enamel matrix derivative on exposed dental pulp

Direct pulp capping procedure is a therapeutic application of a drug on exposed tooth pulp in order to ensure the closure of the pulp chamber and to allow the healing process to take place. The aim of this study was to examine the histological effects of Emdogain® on exposed tooth pulp of a Vietnamese pig (Sus scrofa verus). The study comprised 20 teeth of a Vietnamese pig. After class V preparation on the buccal surfaces of incisors, canines and first premolars, pulp was exposed. In the experimental group, the perforations were capped with Emdogain® (Straumann, Basel, Switzerland), while in the control group pulp capping was performed with MTA® (Dentsply Tulsa Dental, Johnson City, TN, USA). All cavities were restored with glass-ionomer cement (GC Fuji VIII, GC Corporation, Tokyo, Japan). The observational period was 28 days, after which the animal was sacrificed and histological preparations were made. A light microscope was used to analyze dentin bridge formation, tissue reorganization and inflammation, and the presence of bacteria in the pulp. The formation of dentin bridge was observed in the experimental and control groups. Inflammation of the pulp was mild to moderate in both groups. Angiogenesis and many odontoblast-like cells, responsible for dentin bridge formation, were observed. Necrosis was not observed in any case, nor were bacteria present in the pulp. Histological analysis indicated a favorable therapeutic effect of Emdogain® Gel in direct pulp capping of Vietnamese pigs. Pulp reaction was similar to that of MTA®.

Is Pulp Inflammation a Prerequisite for Pulp Healing and Regeneration?

The importance of inflammation has been underestimated in pulpal healing, and in the past, it has been considered only as an undesirable effect. Associated with moderate inflammation, necrosis includes pyroptosis, apoptosis, and nemosis. There are now evidences that inflammation is a prerequisite for pulp healing, with series of events ahead of regeneration. Immunocompetent cells are recruited in the apical part. They slide along the root and migrate toward the crown. Due to the high alkalinity of the capping agent, pulp cells display mild inflammation, proliferate, and increase in number and size and initiate mineralization. Pulp fibroblasts become odontoblast-like cells producing type I collagen, alkaline phosphatase, and SPARC/osteonectin. Molecules of the SIBLING family, matrix metalloproteinases, and vascular and nerve mediators are also implicated in the formation of a reparative dentinal bridge, osteo/orthodentin closing the pulp exposure. Beneath a calciotraumatic line, a thin layer identified as reactionary dentin underlines the periphery of the pulp chamber. Inflammatory and/or noninflammatory processes contribute to produce a reparative dentinal bridge closing the pulp exposure, with minute canaliculi and large tunnel defects. Depending on the form and severity of the inflammatory and noninflammatory processes, and according to the capping agent, pulp reactions are induced specifically.

Endodontology: An Integrated Biological and Clinical View

This book presents a comprehensive overview of endodontics from both a clinical and a biologic perspective. It contains various user-friendly features, including high-quality clinical, radiographic, and histologic images with detailed textual explanations; case studies with thorough documentation; and concluding remarks that summarize the major points of each chapter. These features contribute to easy reading and understanding of the written topics. There are a total of 10 chapters that cover, in general, the normality, disease, treatment, and healing aspects of dentin-pulp complex and periradicular tissues. Chapter 1, ‘‘Dentin-Pulp Complex and Periradicular Tissue,’’ provides an in-depth review of these structures at a microscopic level. It includes numerous unique histologic images that show cellular organization within the dentin-pulp complex. This chapter sets the foundation for the remaining chapters. The first half of Chapter 2, ‘‘Pulp Response to Caries and Restorative Procedures,’’ describes the effect of variable carious lesions and the resulting pulp reactions at a microscopic level. The authors include beautiful illustrations along with clinical, radiographic, and histologic images. The second half of this chapter presents clinical and biologic principles of restorative adhesive materials that are complimented by supporting literature and case studies. Chapter 3, ‘‘Vital Pulp Therapy,’’ offers an overview of various vital pulp management procedures. This chapter also features excel-

The Cracked Tooth: Histopathologic and Histobacteriologic Aspects

IntroductionThe diagnosis and treatment planning of cracked teeth depend on the understanding of how cracks affect the surrounding tissues. This study evaluated the dentin and pulp conditions in teeth affected by cracks and attrition. MethodsSpecimens under investigation included 12 cracked posterior teeth and 8 teeth with severe attrition. These teeth were obtained consecutively in a private practice and were extracted for reasons not related to this study. Teeth were processed for histopathologic and histobacteriologic analyses. ResultsCracks were histologically detected in all specimens, including the teeth with severe attrition. The cracks in all teeth were colonized by bacterial biofilms. One tooth showed several craze lines in the enamel, one of which reached dentin to a shallow depth. In some teeth, the crack ended in the dentin. Dentinal tubules were invaded by bacteria, especially when the crack extended perpendicularly into the dentin. Severe accumulations of inflammatory cells were present in the pulp zone subjacent to tubules involved with the crack. In many cases, the crack extended to the pulp, leading to reactions with intensities ranging from acute inflammation to total pulpal necrosis. Symptoms occurred in most cases in which the pulp was affected. In some cases, polymorphonuclear neutrophils were seen migrating from the pulp into the crack space and facing the bacterial biofilm located therein. Severe pulp reactions were also observed when the crack extended to the pulp chamber floor. ConclusionsCracks are always colonized with bacterial biofilms. The pulp tissue response varies according to the location, direction, and extent of the crack.

Comparison of pulp response to mineral trioxide aggregate and a bioceramic paste in partial pulpotomy of sound human premolars: a randomized controlled trial

This randomized clinical trial evaluated clinical sign/symptoms as well as histological pulp reactions in terms of inflammation and mineralized bridge formation after partial pulpotomy of sound human premolars and placement of a bioceramic paste (iRoot BP) or tooth-colored ProRoot MTA as pulp-covering biomaterials. Twenty-four human sound premolars were randomly allocated into two experimental groups (n = 12) treated either with iRoot BP or MTA subsequent to partial pulpotomy. Six weeks after treatment, clinical sign/symptoms and radiographic changes were evaluated. The teeth were then extracted and examined histologically for inflammatory status of the pulp, formation of hard tissue bridge and appearance of the bridge. In terms of pulp inflammation and dentinal bridge formation, the Mann-Whitney U, and for clinical signs, the chi-square test was used (α = 0.05). In terms of pulp inflammation, formation of hard tissue bridge and its appearance, the differences between the two experimental groups were not significant. However, clinical sensitivity to cold was significantly less for teeth treated with MTA (P < 0.05). All cases had formed a hard tissue bridge, and none of the specimens in either group had pulpal necrosis. When treating teeth with healthy pulps, the response to partial pulpotomy treatment with both MTA and iRoot BP was favourable. However, pulps covered with iRoot BP were more sensitive to cold stimuli.

Histological evaluation of direct pulp capping with novel nanostructural materials based on active silicate cements and Biodentine® on pulp tissue

The aim of this study was to examine the effect of Biodentine® and two new nanostructured materials based on active silicate cements on exposed tooth pulp of Vietnamese pigs. The study comprised 40 teeth in two Vietnamese pigs (24 months old). After class V cavity preparation, the pulp on each tooth was exposed using a small round bur. The following materials were applied on pulp exposures: Biodentine® (10 teeth), ALBO MPCA-I (10 teeth), and ALBO MPCA-II (10 teeth). In the control group, exposed pulp was covered with ProRoot MTA® (10 teeth). After the observation period of 28 days, the animals were sacrificed and the teeth prepared for histological analysis. Light microscope was used for the analysis of dentin bridge formation, tissue reorganization and inflammation, and the presence of bacteria in the pulp. In the group of Biodentine®, a complete dentin bridge was noted in 3 cases, while incomplete dentin bridge in the form of dental islets was detected in 4 cases. Nanostructured material ALBO-MPCA I provided complete dentin bridge formation in 5 teeth, in 3 teeth the formed dentin bridge was incomplete. ALBO MPCA-II showed complete closure of the pulp opening by dentin bridge in 4 samples, while in the same number of teeth it was incomplete. In the control group, 4 teeth showed a complete dentin bridge, whereas in 6 teeth it was incomplete. Histological analysis indicated favourable therapeutic effects of Biodentine® and the two materials ALBO-MPCA I and ALBO-MPCA II after teeth pulp capping in Vietnamese pigs. Pulp reaction was similar to that caused by ProRoot MTA®.

The possibility of genistein as a new direct pulp capping agent

Genistein, kind of soy isoflavones, is well-known as natural ingredients and consumed as health foods and supplements. They are expected to improve renal function. They have high-affinity to estrogen receptor β expressed predominantly in bone tissue, they prevent osteoporosis specifically and safely. We examined whether genistein can be a new direct capping agent. In this study, we examined the effect of genistein for the proliferation and differentiation of rat dental pulp cells in vitro and the ability of tertiary dentin formation in vivo. As a result, rat dental pulp cells with genistein were increased activity of ALPase and showed alizarin red positive-staining. Calcification-related genes expression has been confirmed by the addition of genistein. From in vivo study, high quality of tertiary dentin formation and minor pulp reaction were observed. From these findings, it was suggested that genistein may be useful agent for direct pulp capping.

A histological study of pulp reaction to various water/powder ratios of white mineral trioxide aggregate as pulp-capping material in human teeth: a double-blinded, randomized controlled trial

To compare the histological pulp reaction to various water/powder ratios of white mineral trioxide aggregate (MTA) as a pulp-capping material in healthy human teeth. Twenty-nine disease-free maxillary and mandibular third molar teeth, scheduled for extraction, were exposed mechanically and then capped with 0.28, 0.33 and 0.40 water/powder ratios of white MTA (ProRoot; Dentsply Maillefer, Ballaigues, Switzerland) and restored with glass ionomer. After 30 days, the teeth were extracted, resected apically and immersed in 10% formalin. For histological processing, the teeth were sectioned buccolingually in 5-μm-thick slices, stained with Haematoxylin and Eosin and evaluated by a light microscope. Samples were evaluated for intensity and type of inflammation, presence of necrosis, as well as continuity, morphology and thickness of calcified bridges. The data were analysed by Kruskal-Wallis and Mann-Whitney tests. There were no significant differences in the diameter, morphology and continuity of the calcified bridges, intensity and type of inflammation or presence of necrosis (P > 0.05) in the pulps covered by MTA with various water/powder ratios. Two teeth failed to display a calcified bridge, and one had a pulp necrosis. Water-to-powder ratios of MTA had no significant influence on the histological outcome of direct pulp capping on healthy pulps.

Microscopic evaluation of the human dental pulp after full crown cementation with resin cement

This study evaluated microscopically the dental pulp reactions in human premolars prepared for metaloceramic crowns cemented with different luting agents and also measured the remaining dentin thickness (RDT) of the prepared teeth. Twenty-five teeth were selected from patients that needed exodontia for orthodontic reasons and were randomly divided in three groups: group 1- five teeth were not prepared to serve as a positive control group; groups - 2, and 3 the teeth were prepared for metaloceramic crowns cemented with calcium-hydroxide cement (Life) and resin cement (Panavia Ex 21), respectively. After the final cementation, the teeth remaining in function for periods of seven and forty-five days and were extracted and prepared for microscopic analysis of pulp tissue and detection of presence of bacteria in the dentin tubules. The RDT were measured in 6 different regions of the prepared surface and presented a mean thickness ranging from 1.53 to 1.58 mm. The microscopic analysis did not show an inflammatory reaction of the pulp and bacteria were not found in the dentinal tubules. The resin cement evaluated in this study showed to be as biocompatible as calcium- hydroxide cement and therefore there should not be a clinical preoccupation regarding to pulp reaction.

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

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. 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. 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. 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.