Effects of mineral trioxide aggregate and methyl sulfonyl methane on pulp exposure via RUNX2 and RANKL pathways.

The aim of this study was to determine the therapeutic effects of mineral trioxide aggregate (MTA) and methyl sulfonyl methane (MSM) on pulp damage due to pulp exposure through the RUNX2 and RANKL pathways. Seventy-two male Sprague-Dawley rats aged 4-6 months and weighing 250-300 g were divided into healthy, control, MTA, and MSM groups. After experimental applications, all rats at 2, 4, and 8 weeks were killed anesthetically with xylazine hydrochloride (Rompun, Bayer) 30 mg/kg and ketamine hydrochloride (Ketalar, Pfizer) 50 mg/kg injections (i.p.). We observed that necrotic odontoblasts, edema, inflammation, and vascular congestion findings were reduced from week 2 to week 8 in the MSM treatment group after pulp capping compared to the control group and MTA group. Similarly, we found a decrease in RUNX2 and RANKL levels in the MSM application group compared to the control and MTA groups (p < 0.05). MSM material has shown therapeutic effects on pulp capping treatment-induced pulp injury via increased RUNX2 ve RANKL expression.

MTA and ferric sulfate in pulpotomy outcomes of primary molars: a systematic review and meta-analysis.

OBJECTIVE: Methods of systematic review and meta analysis were employed to compare the success rate of pulpotomy of primary molars using mineral trioxide aggregate (MTA) and ferric sulfate (FS) as two regenerative and preservative agents, respectively. STUDY DESIGN: After raising a PICO question (In pulpotomy of vital carious-exposed primary molars, how does MTA compare to FS in terms of clinical and radiographic outcomes?) and determining the search strategy, MeSH-matching keywords were searched in four electronic databases and retrieved papers were examined in titles, and if necessary abstracts and full texts, to be relevant. Randomized clinical trials (RCTs) evaluating pulpotomy of vital primary molars after carious/traumatic exposure conducted with either FS or MTA, with at least a 6-month recall, tooth restorability, and those considering clinical and radiographic signs/symptoms, were included. The nonrandomized allocation and absence of comparison between the treatment groups caused the exclusion of the article. The quality of the RCTs and also their risk of bias (low, moderate, high), were assessed using a modification of van Tulder list; for meta-analysis of the matching studies, the extracted data were analyzed by Mantel Hanszel analysis. RESULTS: A total number of 620 articles were found. After exclusion of the common titles and application of the eligibility criteria, 4 RCTs [12-month follow-up: n=3, 24-month follow-up: n=4, in total: 264 teeth) comparing MTA and FS, were selected. It was showed that the 12-month outcome of both materials were similar [RR= 0.642 (CI 95%: 0.225-1.833, P=0.407)], while the two-year follow-up results revealed significant differences in treatment outcome, in favor of MTA [RR was 0.300 (CI 95%: 0.132-0.683, P=0.004)]. CONCLUSION: MTA demonstrated superior long-term treatment outcomes in pulpotomy of primary molars than FS.

Primate pulpal healing after exposure and TheraCal application.

AIM: The purpose of this in vivo study was to compare the effectiveness of a new light cured resin based dicalcium/tricalcium silicate pulp capping material (TheraCalLC, Bisco), pure Portland cement, resin based calcium hydroxide or glass ionomer in the healing of bacterially contaminated primate pulps. STUDY DESIGN: The experiment required four primates each having 12 teeth prepared with buccal penetrations into the pulpal tissues with an exposure of approximately 1.0 mm. The exposed pulps of the primate teeth were covered with cotton pellets soaked in a bacterial mixture consisting of microorganisms normally found in human pulpal abscesses. After removal of the pellet, hemostasis was obtained and the pulp capping agents applied. The light cured resin based pulp capping material (TheraCal LC) was applied to the pulpal tissue of twelve teeth with a needle tip syringe and light cured for 15 seconds. Pure Portland cement mixed with a 2% Chlorhexidine solution was placed on the exposed pulpal tissues of another twelve teeth. Twelve additional teeth had a base of GIC applied (Triage, Fuji VII GC America) and another twelve had a pulp cap with VLC DYCAL (Dentsply), a light cured calcium hydroxide resin based material. The pulp capping bases were then covered with a RMGI (Fuji II LC GC America). The tissue samples were collected at 4 weeks. The samples were deminerilized, sectioned, stained and histologically graded. RESULTS: There were no statistically significant differences between the groups in regard to pulpal inflammation (H = 0.679, P = 1.00). However, both the Portland cement and light cured TheraCal LC groups had significantly more frequent hard tissue bridge formation at 28 days than the GIC and VLC Dycal groups (H = 11.989, P = 0.009). The measured thickness of the hard tissue bridges with the pure Portland and light cured TheraCal LC groups were statistically greater than that of the other two groups (H = 15.849, P = 0.002). In addition, the occurrence of pulpal necrosis was greater with the GIC group than the others. Four premolars, one each treated according to the protocols were analyzed with a microCT machine. The premolar treated with the light cured TheraCal LC demonstrated a complete hard tissue bridge. The premolar treated with the GIC did not show a complete hard tissue bridge while the premolar treated with VLC Dycal had an incomplete bridge. The pure Portland with Chlorhexidine mixture created extensive hard tissue bridging. CONCLUSION: TheraCal LC applied to primate pulps created dentin bridges and mild inflammation acceptable for pulp capping.

Effect of white mineral trioxide aggregate compared with biomimetic carbonated apatite on dentine bridge formation and inflammatory response in a dental pulp model.

AIM: To evaluate the effects of apatite precipitation on the biocompatibility and hard tissue induction properties of white mineral trioxide aggregate (WMTA) in a dental pulp model. METHODOLOGY: Pulp exposures were created on the axial walls of 32 sound canine teeth of eight dogs. Four additional sound teeth served as controls. The pulps were capped either with WMTA or apatite derivatives [biomimetic carbonated apatite (BCAp)] in the interaction of WMTA with a synthetic tissue fluid and restored with zinc oxide-eugenol cement. After 7 and 70 days, the animals were killed, and the histological specimens taken from the teeth were stained with haematoxylin and eosin for histomorphological evaluation. The Brown and Brenn technique was employed to stain bacteria. The data were subjected to nonparametric Kruskall-Wallis analysis and Mann-Whitney U_tests. RESULTS: Biomimetic carbonated apatite did not induce hard tissue bridge formation. WMTA performed significantly better than BCAp in this respect at both periods (P < 0.05). BCAp was associated with a significantly greater inflammatory response as compared with WMTA after 7 days (P < 0.05). Both materials were associated with similar reactions after 70 days (P >0.05). CONCLUSIONS: White mineral trioxide aggregate induced hard tissue formation via a mechanism other than that postulated via apatite formation.

Proliferation of rat molar pulp cells after direct pulp capping with dentine adhesive and calcium hydroxide.

The aim was to evaluate the proliferation of pulp cells 1, 3 and 7 days after direct pulp capping with the dentine adhesive Gluma Comfort Bond (GCB) and to compare it with calcium hydroxide (Ca(OH)(2)). An occlusal cavity was prepared in 72 molar teeth of 36 Wistar rats. Then GCB or Ca(OH)(2) was placed on the exposed pulp. All cavities were restored with composite. After 1, 3 and 7 days, the animals were sacrificed. One hour prior sacrification, 5-bromo-2'-desoxyuridine (BrdU) was injected into the intraperitoneal cavity for immunohistological analysis of 18 animals. BrdU was incorporated into the DNA to tag proliferating cells using an antibody staining. Three animals served as controls and were not further treated. The number of the tagged cells was statistically analysed by comparing the results of the three groups. In 18 rats, routine histological analysis was performed in order to evaluate the pulp tissue for bacterial infection, inflammatory cells and necrosis. The marked cells were identified as fibroblasts, endothelial cells (after 1, 3 and 7 days) and Höhl cells (after 7 days). One day after capping, significantly more cells were stained in the GCB than in the Ca(OH)(2) group (p < 0.05). After 3 days, significantly more cells were stained in the GCB than in the Ca(OH)(2) and the control group (p < 0.016). Direct contact of GCB with pulp tissue leads to an increased formation of granulation tissue (fibroblasts, endothelial cells) because of an inflammatory reaction. This may be explained by missing antibacterial effect and foreign body reactions. Also, GCB may have a negative effect on Höhl cells.

Early response of mechanically exposed dental pulps of swine to antibacterial-hemostatic agents or diode laser irradiation.

OBJECTIVES: The purpose of this study was to compare the effectiveness of an antibacterial and hemostatic agent to diode laser irradiation in the healing of mechanically exposed porcine pulps. MATERIALS AND METHOD: The experiment required three adult swine (Sus scrofa domestica, Yorkshire) with 36 teeth prepared with occlusal penetrations into the pulpal tissues. The preparations were performed under general anesthesia and the pulps were exposed using high speed instrumentation with rubber dam isolation and a disinfected field. Following instrumentation the coronal pulpal tissue was amputated and immediately treated with ferric sulfate and chlorhexidine semi-gel (12), diluted Buckley' formocresol solution (12) for 5 minutes or laser irradiation with a diode laser (12). After treatment, hemostasis was obtained and a ZOE base applied to the treated pulps (36). The pulpal bases were all covered with a RMGI (Fuji II LC). The tissue samples were collected at 4 weeks (28 days). Following fixation, the samples were de-mineralized, sectioned, stained and histologically graded with a scale of 0-4. RESULTS: The treatment groups were statistically different with the Laser Treated Group demonstrating the least inflammation. CONCLUSION: Pulpotomy treatment with the KaVo Gentle Ray Diode Laser demonstrated significantly less inflammation than the other two pulpal therapy modalities. The ferric sulfate and chlorhexidine mixture demonstrated the greatest inflammation as histologically graded. Also, the histological sections of pulpotomized swine teeth treated with the ferric sulfate and chlorhexidine mixture presented with black pigmented areas in the pulp and surrounding tissue. The formocresol group (clinical standard) and the diode laser group did not present with the black precipitate.

Evaluation of dentinogenesis inducer biomaterials: an in vivo study.

When exposure of the pulp to external environment occurs, reparative dentinogenesis can be induced by direct pulp capping to maintain pulp tissue vitality and function. These clinical situations require the use of materials that induce dentin repair and, subsequently, formation of a mineralized tissue. OBJECTIVE: This work aims to assess the effect of tricalcium silicate cements and mineral trioxide aggregate cements, including repairing dentin formation and inflammatory reactions over time after pulp exposure in Wistar rats. METHODOLOGY: These two biomaterials were compared with positive control groups (open cavity with pulp tissue exposure) and negative control groups (no intervention). The evaluations were performed in three stages; three, seven and twenty-one days, and consisted of an imaging (nuclear medicine) and histological evaluation (H&E staining, immunohistochemistry and Alizarin Red S). RESULTS: The therapeutic effect of these biomaterials was confirmed. Nuclear medicine evaluation demonstrated that the uptake of 99mTc-Hydroxymethylene diphosphonate (HMDP) showed no significant differences between the different experimental groups and the control, revealing the non-occurrence of differences in the phosphocalcium metabolism. The histological study demonstrated that in mineral trioxide aggregate therapies, the presence of moderate inflammatory infiltration was found after three days, decreasing during follow-ups. The formation of mineralized tissue was only verified at 21 days of follow-up. The tricalcium silicate therapies demonstrated the presence of a slight inflammatory infiltration on the third day, increasing throughout the follow-up. The formation of mineralized tissue was observed in the seventh follow-up day, increasing over time. CONCLUSIONS: The mineral trioxide aggregate (WhiteProRoot®MTA) and tricalcium silicate (Biodentine™) present slight and reversible inflammatory signs in the pulp tissue, with the formation of mineralized tissue. However, the exacerbated induction of mineralized tissue formation with the tricalcium silicate biomaterial may lead to the formation of pulp calcifications.

Comparison of enamel matrix derivative versus formocresol as pulpotomy agents in the primary dentition.

The purpose of this study was to compare the clinical and radiographic success rates of two different pulpotomy agents: one novel agent, the biologically active odontogenic protein enamel matrix derivative (EMD) versus formocresol (FC). A randomized, single-blind, split-mouth study was used with a sample of 15 children aged 4 to 7 years (mean age, 5 +/- 0.73 years). A total of 15 pairs of teeth, 1 pair per child, were selected for treatment. One tooth from each pair was randomly assigned to either the EMD pulpotomy group or the FC pulpotomy group. All teeth were followed up clinically and radiographically at 2, 4, and 6 months. After 6 months, the clinical success rates for the FC and EMD groups were 67% and 93%, respectively. Although most likely clinically relevant, the clinical success rate difference after 6 months was not statistically significant. After 6 months, the radiographic success rates for the FC and EMD groups were 13% and 60 %, respectively. There was a statistically significant difference at p < or = 0.05. The clinical and radiographic assessment of EMD pulpotomized teeth in this study offers preliminary evidence that EMD is a promising material which may be as successful, or more so, than other pulpotomy agents.

Histological evaluation of direct pulp capping with a self-etching adhesive and calcium hydroxide on human pulp tissue.

AIM: To evaluate human pulp tissue response following direct pulp capping with a self-etching adhesive: Clearfil SE BOND (SB). METHODOLOGY: Forty-five sound teeth from 20 subjects were used. Forty-one teeth had their pulp mechanically exposed at the base of a Class 1 cavity preparation and were divided into two groups: group 1, teeth were capped with SB (n = 21), and group 2, with calcium hydroxide cement (CH) (n = 20). Four teeth were maintained intact as an untreated control group. After 7, 30 and 90 days, respectively, 15 teeth were extracted and processed for light microscopic examination. Pulp healing and bacterial microleakage were assessed by haematoxylin and eosin, Masson trichrome and Brown and Brenn stain techniques. The data were analysed statistically by using the Mann-Whitney U test. RESULTS: After the 7-day observation period, the inflammatory reaction in the SB group was slight and significantly less severe than that of the CH group (P < 0.05). After the 30- and 90-day observation periods, the inflammatory reaction was slight in both groups, but specimens with dentine bridge formation in the SB group were significantly less common than those in the CH group (P < 0.05). CONCLUSIONS: Clearfil SB had good biocompatibility with human pulp tissue, but its ability to induce reparative dentine was significantly lower than that of calcium hydroxide.

Efficacy of ferric sulphate as a pulpotomy medicament in primary molars: an evidence based approach.

AIM: To evaluate the available evidence on the efficacy of ferric sulphate (FS) compared to other pulpotomy medicaments in primary molars. METHODS: A comprehensive literature search was conducted through five databases (PubMed, Ovid®, EBSCOhost, Cochrane Library and ProQuest) and only those papers which met the inclusion criteria were accepted. The quality of the studies used for systematic review was rated by two independent researchers based on Fuks and Papagiannoulis (Eur Arch Paediatr Dent 7:64-71, 2006) criteria and graded as A (38-42), B1 (32-37), B2 (25-31), C (≤ 24). Inter-examiner reliability was measured using Kappa statistics. RESULTS: A total of 1371 studies were available, of which only two studies full-text articles were included for quality assessment with an excellent inter-researcher agreement (k = 0.9). The comprehensive search revealed that, none of the 20 studies obtained grade A. Only three studies were graded as B1, 5 studies received grade B2 and 12 studies attained grade C. Only 4 prospective randomised clinical trials reported high success rate with FS compared to other materials. Remaining 14 studies revealed low success rate with FS compared to other pulpotomy medicaments. CONCLUSION: There is insufficient evidence to support the application of FS as a pulpotomy medicament in primary molars in the existing English literature. Hence, properly planned randomised clinical trials with large sample size and long-term follow up are needed to support FS as an effective pulpotomy medicament compared to other traditional and new medicaments.

Formation of dentin-like particles in dentin defects above exposed pulp by controlled release of fibroblast growth factor 2 from gelatin hydrogels.

The induction of dentin formation on exposed dental pulp is a major challenge in research on the regeneration of the dentin-pulp complex. We examined the effects of fibroblast growth factor 2 (FGF2), which was delivered in either a collagen sponge (noncontrolled release) or incorporated into gelatin hydrogels (controlled release), on the formation of dentin in exposed rat molar pulps. During the early phase of pulp wound healing, pulp cell proliferation and invasion of vessels into dentin defects above exposed pulp were induced in both groups. In the late phase, the induction of dentin formation was distinctly different between the 2 types of FGF2 release. The noncontrolled release of free FGF2 from collagen sponge induced excessive reparative dentin formation in the residual dental pulp, although dentin defects were not noted. In contrast, controlled release of FGF2 from gelatin hydrogels induced the formation of dentin-like particles with dentin defects above exposed pulp. These results suggest the possibility of a novel therapeutic approach for dentin-pulp complex by controlled release of bioactive FGF2.

SEM evaluation of neodentinal bridging after direct pulp protection with mineral trioxide aggregate.

The purpose of this study was to observe the basic morphology and determine the chemical composition of neodentinal bridges adjacent white mineral trioxide aggregate (WMTA) when used as a direct pulp capping material. The experimental procedures were performed on six intact dogs' teeth. The pulps were exposed and cavities were filled with WMTA. After 2 weeks, neodentinal bridge formation was evaluated by scanning electron microscope (SEM) of cross-sections of the specimens and electron probe microanalysis (EPMA) of the pulpal surfaces. Results of SEM observation showed that the most characteristic reaction of pulp cells was the intimate connection of cell processes and secreted extracellular fibres with the crystals of the pulp capping material. Results of EPMA indicated that the mineralisation of neodentinal bridge formation occurred progressively from the periphery to the central area. Based on these results, it appears that WMTA has the potential to be used as a direct pulp capping material during vital pulp therapy.

Histological Effects of Enamel Matrix Derivative on Exposed Dental Pulp.

INTRODUCTION: 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. OBJECTIVE: The aim of this study was to examine the histological effects of Emdogain® on exposed tooth pulp of a Vietnamese pig (Sus scrofa verus). METHODS: 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. RESULTS: 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. CONCLUSION: 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®.

Evaluation of dentinogenesis inducer biomaterials: an in vivo study

Abstract When exposure of the pulp to external environment occurs, reparative dentinogenesis can be induced by direct pulp capping to maintain pulp tissue vitality and function. These clinical situations require the use of materials that induce dentin repair and, subsequently, formation of a mineralized tissue. Objective: This work aims to assess the effect of tricalcium silicate cements and mineral trioxide aggregate cements, including repairing dentin formation and inflammatory reactions over time after pulp exposure in Wistar rats. Methodology: These two biomaterials were compared with positive control groups (open cavity with pulp tissue exposure) and negative control groups (no intervention). The evaluations were performed in three stages; three, seven and twenty-one days, and consisted of an imaging (nuclear medicine) and histological evaluation (H&E staining, immunohistochemistry and Alizarin Red S). Results: The therapeutic effect of these biomaterials was confirmed. Nuclear medicine evaluation demonstrated that the uptake of 99mTc-Hydroxymethylene diphosphonate (HMDP) showed no significant differences between the different experimental groups and the control, revealing the non-occurrence of differences in the phosphocalcium metabolism. The histological study demonstrated that in mineral trioxide aggregate therapies, the presence of moderate inflammatory infiltration was found after three days, decreasing during follow-ups. The formation of mineralized tissue was only verified at 21 days of follow-up. The tricalcium silicate therapies demonstrated the presence of a slight inflammatory infiltration on the third day, increasing throughout the follow-up. The formation of mineralized tissue was observed in the seventh follow-up day, increasing over time. Conclusions: The mineral trioxide aggregate (WhiteProRoot®MTA) and tricalcium silicate (Biodentine™) present slight and reversible inflammatory signs in the pulp tissue, with the formation of mineralized tissue. However, the exacerbated induction of mineralized tissue formation with the tricalcium silicate biomaterial may lead to the formation of pulp calcifications

Comparison of acetaminophen, ibuprofen, and nabumetone therapy in rats with pulpal pathosis.

The purpose of this study was to determine if daily treatment with acetaminophen, ibuprofen, or nabumetone would alter prostaglandin E2 (PGE2)/leukotriene B4 (LTB4) synthesis in exposed, infected dental pulp and periradicular tissue in rats. Dental pulp of the bilateral first and second mandibular molars were exposed for 15 or 24 days. Rats were divided into four groups. A daily pharmacological oral dose of one of the medications or the suspending solution alone was administered to the designated group. Eicosanoids were extracted from pulpal and periradicular tissues and assayed. PGE2 was significantly elevated in pulp-exposed, nontreated rats and was significantly reduced in the ibuprofen- and nabumetone-treated groups. LTB4 was significantly increased in all pulp-exposed groups at 15 days when compared with control nonexposed groups. Results showed that only ibuprofen reduced LTB4 in the exposed dental pulp at 24 days, although it did not do so at 15 days. Repetitive treatment with acetaminophen did not suppress PGE2/LTB4 in pulp-exposed molars.

Differential repair responses in the coronal and radicular areas of the exposed rat molar pulp induced by recombinant human bone morphogenetic protein 7 (osteogenic protein 1).

Bone morphogenetic protein 7 (BMP 7), also termed osteogenic protein 1, a member of the transforming growth-factor superfamily, was examined for its efficacy in inducing reparative dentinogenesis in the exposed pulps of rat molars. To determine if the reaction was dose-dependent, collagen pellets containing 1, 3 or 10 microgram of recombinant BMP 7 were inserted in intentionally perforated pulps (10-12 pulps per group) in the deepest part of half-moon class V-like cavities cut in the mesial aspect of upper first molars. As controls, the collagen carrier (CC group) alone and calcium hydroxide (Ca group) were used as capping agents. All cavities were then restored with a glass-ionomer cement. Half of the animals were killed after 8 days and the other half after 28 days, by intracardiac perfusion of fixative. The molars were processed for histological evaluation by light microscopy. No difference in effect could be detected between the three concentrations of BMP 7 groups at either time interval. After 8 days, all groups showed varying inflammation, from mild of severe, and the Ca group demonstrated early formation of a reparative dentine bridge. At 28 days the CC group displayed irregular osteodentine formation, leaving some unmineralized areas at the exposure site and interglobular unmineralized areas containing pulp remnants. In the Ca-treated pulps, the initial formation of thick reparative osteodentine bridges that sealed more or less completely the pulp perforation was followed, in the deeper part, by irregular tubular dentine. In most BMP 7-treated specimens, the initial inflammation has resolved at 8 days and at 28 days heterogeneous mineralization or osteodentine filled the mesial coronal pulp. They also had complete filling of the radicular pulp by homogenous mineralization in the mesial root; this reaction was found in 11 teeth in the BMP 7 group, one tooth in the CC group an none of the Ca group. These results emphasize the biological differences the coronal and radicular parts of the pulp, and the potential of bioactive molecules such as BMP 7 to provide an a alternative conventional endodontic treatments.

Cytotoxic effects of cleansing solutions recommended for chemical lavage of pulp exposures.

PURPOSE: To evaluate the in vitro cytotoxic effects of three cleansing solutions used for chemical lavage of pulp exposures. MATERIALS AND METHODS: The immortalized odontoblast cell line (MDPC-23) was plated (30,000 cells/cm2) and incubated for 72 hrs in 24-well dishes. After counting the cell number under inverted light microscopy, 20 microl of the experimental and control solutions were added to 980 microl of fresh culture medium. Then, hydrogen peroxide (3%, H2O2), sodium hypochlorite (6%, NaOCl) or calcium hydroxide-saline solution (5g of Ca(OH)2 in 10 ml of sterile distilled water) were added to wells for experimental Groups 1, 2 and 3, respectively. The positive and negative control groups received Syntac Sprint bonding agent (SS) and phosphate buffered saline (PBS), respectively. Following incubation for 120 min the cell number was counted again, the cell morphology was evaluated by scanning electron microscopy (SEM) and the cell metabolism was determined by the methyltetrazolium (MTT) assay. The scores obtained from cell counting and MTT assay were analyzed with an ANOVA followed by Fisher's PLSD tests. RESULTS: H2O2, NaOCl solutions, and SS bonding agent were more cytotoxic than Ca(OH)2 or PBS. In the groups with H2O2 or SS, only a few cells remained attached to the bottom of wells. The difference between these two groups was not statistically significant. H2O2, NaOCl and SS depressed the mitochondrial enzyme response by 97.7%, 97.3%, and 95.0%, respectively. On the other hand, Ca(OH)2 depressed the metabolic activity of cells by only 5%. While H2O2, NaOCl and SS caused extreme changes on the cell morphology, neither Ca(OH)2 nor PBS promoted dramatic changes in the cell morphology.

Pulp response to direct capping with an adhesive system.

PURPOSE: To evaluate the pulp response following direct pulp capping with an adhesive system (Prime & Bond 2.0 - PB 2.0) and a zinc-oxide eugenol cement (ZOE) on pulp exposures in rat molar teeth. MATERIALS AND METHODS: Forty-eight Class I cavities were prepared on the occlusal surface of molar teeth of rats (Rattus Norvegicus, Holtzman). Pulp exposures performed on the cavity floor were capped either with the adhesive system P&B 2.0 or ZOE. After 7, 15, 30, and 60 days, the specimens were processed through H & E and Brown & Brenn staining techniques. RESULTS: Both pulp capping materials allowed pulp repair, characterized by reorganization of a new odontoblast cell layer underlying the dentin bridge formation. However, P&B 2.0 promoted a large zone of cell-rich fibrodentin matrix deposition between the pulp capping material and the dentin bridge, which was deposited far from the pulp exposure site. On the other hand, pulps capped with ZOE showed dentin bridging immediately subjacent to the pulp capping material. In those samples in which microleakage occurred between dental material and cavity walls there was a persistent inflammatory reaction and lack of complete pulp repair.

Development of new adhesive pulp capping materials.

The pulp capping materials currently available do not adhere to dentine but cover it and therefore extensive removal of tooth tissue is necessary to expose sufficient dentine for the adhesives used to secure the restoration (the adhesives do not adhere to the capping material). The authors describe how two new pulp capping materials have been developed, which combine the properties required for pulp capping with an ability to adhere to dentine.

Dentinogenic responses after direct pulp capping of miniature swine teeth with Biodentine.

INTRODUCTION: The aim of this study was to evaluate pulpal responses after experimental direct pulp capping of mechanically exposed teeth with a new calcium silicate-based dentin replacement material. METHODS: Thirty-four anterior and posterior teeth of 3 miniature swine were used. Class V or I cavities were prepared on the buccal or occlusal surfaces, respectively. Pulpal exposures were further performed using a round carbide bur 0.8 mm in diameter. Exposures were treated with white MTA Angelus (Angelus, Londrina, PR, Brazil) or Biodentine (Septodont, Saint Maur des Fosses, France), and the cavities were further restored with Biodentine. The pulpal tissue responses were histologically assessed at postoperative periods of 3 and 8 weeks. Data were statistically analyzed using the Kruskal Wallis and the Mann-Whitney U tests. RESULTS: Inflammatory infiltration or pulp tissue necrosis was not found in any of the specimens. All teeth showed mineralized matrix formation in the form of a complete hard tissue bridge composed of osteodentin or osteodentin followed by a discontinuous or continuous reparative dentin zone. A significantly higher thickness of the hard tissue bridge was found in the group of teeth treated with Biodentine at both 3 and 8 weeks. A number of teeth, which were under root development at the onset of the experimental procedures, exhibited ectopic pulp calcification. CONCLUSIONS: The application of both calcium silicate-based materials in direct contact with the mechanically exposed pulp of healthy miniature swine teeth led to pulp repair with complete hard tissue bridge formation. The thickness of hard tissue bridges was significantly higher after pulp capping with Biodentine.