Clinical Research

Tomographic Evaluation of Reparative Dentin Formationafter Direct Pulp Capping with Ca(OH)2, MTA, Biodentine,and Dentin Bonding System in Human TeethAlicja Nowicka, DDS, PhD,* Gra _zyna Wilk, MD, PhD,† Mariusz Lipski, DDS, PhD,‡

Janusz Ko1ecki, MD, PhD,† and Jadwiga Buczkowska-Radli�nska, DDS, PhD*

Abstract

Introduction: Newmaterials can increase the efficiencyof pulp capping through the formation of a completereparative dentin bridge with no toxic effects. The pre-sent study involved tomographic evaluations of repara-tive dentin bridge formation after direct pulp cappingwith calcium hydroxide, mineral trioxide aggregate(MTA), Biodentine (Septodont, Saint Maur des Foss�es,France), and Single Bond Universal (3M ESPE, Seefeld,Germany) in human teeth. Methods: Forty-fourcaries-free, intact, human third molars scheduled forextraction were subjected to mechanical pulp exposureand assigned to 1 of 4 experimental groups dependingon the pulp capping agent used: calcium hydroxide,MTA, Biodentine, or Single Bond Universal. After6 weeks, the teeth were extracted and processed forcone-beam computed tomographic imaging and histo-logic examination. Tomographic data, including the den-sity and volume of formed reparative dentin bridges,were evaluated using a scoring system. Results: Thereparative dentin formed in the calcium hydroxide,MTA, and Biodentine groups was significantly superiorto that formed in the Single Bond Universal group interms of thickness and volume. The dentin bridges inthe Biodentine group showed the highest average andmaximum volumes. The mean density of dentin bridgeswas the highest in the MTA group and the lowest in theSingle Bond Universal group. Conclusions: The volumeof reparative dentin bridges formed after direct pulpcapping is dependent on the material used. Biodentineand MTA resulted in the formation of bridges with asignificantly higher average volume compared withSingle Bond Universal, and cone-beam computedtomographic imaging allowed for the identificationof the location of dentin bridges. (J Endod2015;41:1234–1240)

From the Departments of *Conservative Dentistry, †General andMedical University, Szczecin, Poland.

Address requests for reprints to Dr Alicja Nowicka, DepartmenSzczecin, Poland. E-mail address: nowicka6@gmail.com0099-2399/$ - see front matter

Copyright ª 2015 American Association of Endodontists.http://dx.doi.org/10.1016/j.joen.2015.03.017

1234 Nowicka et al.

Key WordsBiodentine, calcium hydroxide, cone-beam computed tomographic imaging, direct pulpcapping, mineral trioxide aggregate, Single Bond Universal

The most visible reparative response to pulp exposure is the deposition of repar-ative dentin that provides odontoblasts and other pulp cells and protection

against harmful stimuli (1, 2). Reparative dentin formation can be affected by thepulp capping material, the degree of mechanical injury, and inflammatory andbacterial leakage (3). Currently, none of the commercially available direct pulpcapping materials fulfills all the requirements of dentists despite rapid progressin the field (4–7). Calcium hydroxide (Ca[OH]2) remains the gold standard forthe management of pulp exposure because of its potent antibacterial propertiesand its ability to stimulate reparative dentin formation and, consequently, pulphealing (2, 6, 8, 9). However, Ca(OH)2 is reported to dissolve over time, anddentin bridges adjacent to the material may contain multiple tunnel defects thatopen into the underlying pulp (5, 10–14).

Recent studies showed that other materials and strategies may increase the effi-ciency of pulp capping through the formation of a complete reparative dentin bridgewith no chemical toxic effects, thus providing better results than those provided byCa(OH)2 (12–15). Mineral trioxide aggregate (MTA) is characterized by improvedsealing properties and a greater ability to stimulate reparative dentin formationcompared with Ca(OH)2; however, it has the disadvantages of difficult handling andapplication, a longer binding duration, and a relatively high cost (4, 5, 8, 12–14).Several attempts to improve the binding reaction of MTA by the addition of variousaccelerators and modifiers have been made to provide novel materials that can beeffectively used for direct pulp capping (4, 13). Biodentine (Septodont, Saint Maurdes Foss�es, France) is a new material based on calcium silicates and has propertiessimilar to those of Ca(OH)2 and MTA; furthermore, it overcomes some limitations ofthe latter 2 preparations (14–16). Previous in vitro and in vivo studies confirmedthat Biodentine has a positive effect on pulp cells and promotes reparative dentinformation in a manner similar to MTA (14–19).

In recent years, dentin bonding systems have also been investigated (5–7, 20, 21)as potential direct pulp capping materials because of their superior adhesion todemineralized dentin tissues. Single Bond Universal (3M ESPE, Seefeld, Germany)represents the next generation of bonding systems available to dentists, the so-calleduniversal systems (7, 22). Application of this material on the dentin surface resultsin the formation of a hybrid layer, with superior chemical bonding of the monomer

Dental Radiology, and ‡Preclinical Conservative Dentistry and Preclinical Endodontics, Pomeranian

t of Conservative Dentistry, Pomeranian Medical University, Al.Powsta�nc�ow Wlkp. 72, 70–111

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Clinical Research

10-methacryloxydecyl dihydrogen phosphate to hydroxyapatite (23).However, the effectiveness of this system in reparative dentin formationafter application to exposed pulp remains to be elucidated.

Although the histologic evaluation of dentin bridge sections iscommonly accepted as the gold standard, cone-beam computedtomographic (CBCT) imaging represents an innovative and noninva-sive technique that offers the possibility of studying dental tissuewithout the need to destroy it (24–27). In addition, 3-dimensionalreconstruction of CBCT images eliminates the superimposition of sur-rounding structures (24).

The present study aimed to conduct tomographic evaluations ofreparative dentin bridges formed after direct capping with Ca(OH)2,MTA, Biodentine, and Single Bond Universal in human teeth to verifythe null hypothesis that there is no difference in the quantity and qualityof reparative dentin formation between the evaluated materials used fordirect pulp capping in human teeth.

Materials and MethodsOperative Procedure

The study was conducted in accordance with the tenets of theDeclaration of Helsinki. Forty-four caries-free, intact, maxillary andmandibular third molars from 21 humans aged 19–32 years (mean26 years) scheduled for extraction for orthodontic or surgical purposeswere included. Patients received a thorough explanation of the experi-mental rationale, clinical procedures, and possible complications. Allthe patients gave their informed consent. All experimental protocolswere reviewed and approved by the Local Ethics Committee of Pomer-anian Medical University, Szczecin, Poland (approval number KB–0012/39/11).

A standardized therapeutic procedure was used. According to theoperative protocol, each tooth was radiologically examined to excludethe presence of caries or periapical pathology. Thermal testing(K€altespray; M&W Dental, GmbH, B€udingen, Germany) and electricsensitivity testing (Vitality Scanner pulp vitality tester; SybronEndo, Or-ange, CA) were performed to assess pulp vitality. The teeth were me-chanically cleaned and disinfected with 0.2% chlorhexidine solutionbefore cavity preparation. After the induction of local anesthesia andapplication of a rubber dam, occlusal class I cavities were prepared us-ing sterile round diamond burs at a high speed under air–distilled watercooling. An exposuremeasuring approximately 1.2 mm in diameter wascreated using round carbide burs under air–distilled water cooling.New burs were used for each procedure. Bleeding was controlledwith saline irrigation, and a sterile cotton pellet was placed on thesite of pulp exposure.

The teeth were randomly divided into 4 groups (n = 11 each) de-pending on the pulp capping material used. In group 1 (CH group), theexposed pulp and surrounding dentin were capped with Ca(OH)2pastes Calcipast (Cerkamed, Stalowa Wola, Poland), Life (Kerr Hawe,Salerno, Italy), and Single Bond Universal with Filtec Ultimate (3MESPE) according to the manufacturer’s recommendations. In group 2(MTA), the exposed pulp and surrounding dentin were capped withProRoot White MTA (Dentsply, Tulsa Dental, Tulsa, OK) according tothe manufacturer’s recommendations. After MTA application, the oper-ator laid a flat, water-moistened cotton pellet directly over the materialand provisionally restored the tooth with glass ionomer cement (KetacMolar, 3M ESPE). In group 3 (BIO), the exposed pulp was capped withBiodentine according to the manufacturer’s recommendations. Bio-dentine was also used for the temporary restoration so that the entirecavity was filled with bioactive cement. Patients in both groups 2 and3 returned to the clinic for clinical examination and final compositerestoration after 7 days. The operator additionally verified the setting

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of MTA. In group 4 (SBU), the exposed pulp and surrounding dentinwere capped with Single Bond Universal with Filtec Ultimate accordingto the manufacturer’s recommendations.

Six weeks after application of the pulp capping material, all teethwere extracted with minimum trauma by a designated oral surgeon. Theextracted teeth were then subjected to CBCT imaging and light micro-scopy as described later.

Light MicroscopyAfter fixation for 2 weeks in 10% buffered formalin solution, the

extracted specimens were demineralized in nitric acid and embeddedin paraffin. Two- to 3-mm-thick serial sections cut in the lingual-buccal plane were stained with hematoxylin-eosin (H&E). The Brownand Brenn technique was used to stain bacteria. Coded samples wereused throughout the study to avoid possible bias. Qualitative and quan-titative histopathological analyses were performed on the H&E-stainedspecimens using an optical microscope (Imager D1 Axio; Carl Zeiss,Goettingen, Germany) connected to a high-resolution video camera(Axio Cam MRc5; Carl Zeiss Microimaging, Thornwood, NY). Examina-tions were performed under normal and ultraviolet (UV) light using 38HE (eGFP) and 43 HE (Cy 3) filters (Carl Zeiss, Goettingen, Germany)by an experienced examiner. The amount of hard tissue formation at theinterface of the capping material was analyzed using the previouslydescribed criteria (16).

CBCT ImagingCBCT images (Cranex 3D, No. SE 1100155, Software Version Sca-

nora 5.1.0.9; Soredex, Tuusula, Finland) were obtained to identifyreparative dentin bridges on original and multiplanar reconstructionimages using the dedicated OnDemand3D App 1.0.9.1343 software(Soredex, Tuusula, Finland) (Fig. 1A). Subsequently, a serial profileof the dentin bridge formed from the coronal (the first virtual slice)to the cervical sections (last virtual slice) was ascertained using0.133-mm axial slices of the tooth; this allowed for the calculation ofthe estimated thickness. A series of axial images showing the mineral-ized reparative tissues formed over the exposed pulp are shown inFigure 1B.

The Osirix (Version 4.1.2.32 bit; Pixmeo, Geneva, Switzerland)software was used to analyze the axial images, and the findings fromthe axial and multiplanar reconstruction images were compared withthose of histologic examinations. The width (contrast) and level (bright-ness) of the window (approximately 2000/4500) were used to preciselyshow the plane of the formed bridge, and it was ensured that this planewas consistent with that on the representative histologic section of thethickest reparative dentin bridge (Fig. 2A). The use of the UV filter shaveallowed for further clarification of the dimensions of the bridge(Fig. 2A1 and A2). The boundary between the dentin bridge andpulp tissue was established using the upper limit of the pulp densityand was confirmed from the peak on an individual histogram foreach specimen (Fig. 2B). Then, the dimensions of the dentin bridge ob-tained from histologic examination were transferred to a CBCT image todetermine the boundary between the dentin bridge and the filling.Points were located individually for each tooth at the lower limit ofthe density values to eliminate artifacts. After merging the points, anarc depicting the limiting surface was plotted and used to ascertainthe density of the dentin bridge.

To evaluate the characteristics of each tooth, the densities of thepulp; young dentin, which was located immediately proximal to thepulp; and mature dentin, which was located external to the youngdentin, were determined. The density of young dentin was determinedby drawing an ellipse with a surface area of 500,000 mm2. Mature

Direct Pulp Capping with Ca(OH)2, MTA, and Biodentine 1235

Figure 1. Identification of reparative dentin tissues formed after direct pulp capping with Ca(OH)2. (A) Original and multiplanar reconstruction images obtainedusing CBCT imaging and the dedicated OnDemand3D App 1.0.9.1343 software. (B) A series of axial images showing the newly calcified barrier under Ca(OH)2.

Clinical Research

dentin could be observed in the area immediately adjacent to youngdentin (Fig. 2B).

The area of the dentin bridge was encircled on each reconstructedlayer to establish the spatial structure and calculate the volume using theaforementioned principle and Osirix software. The resulting surfaceswere compared with images of histologic sections of successive toothlayers. Thus, areas of the dentin bridge (regions of interest) obtainedwere summed up to derive the volume (Fig. 2C–F).

The volume of the bridge was measured and assigned to 4 groupsaccording to the authors’ classification: 1, no dentin or unmeasurablevolume of dentin; 2, low volume (<0.1 mm3); 3, moderate volume(0.1–0.5 mm3); and 4, high volume (>0.5 mm3). Because the mini-mum measurable distance was limited by tomography resolution,very small bridges were measurable only on histologic images.

Statistical AnalysisAll continuous variables were checked for normality of distribu-

tion using the Kolmogorov-Smirnov test. Statistical differences betweenthe 2 groups were identified using the Student t test and the Mann-Whitney U test. Analysis of variance and the Kruskal-Wallis test wereapplied for analysis of the groups. Any correlations between discretevariables were studied using the Pearson chi-square test and the Fisherexact test. Differences were considered statistically significant at P< .05.

ResultsLight Microscopy

Clinically, pulp capping success was found in all teeth after 6weeks. No detectable periradicular radiographic changes were

1236 Nowicka et al.

observed. Teeth from all groups responded positively to electric pulptesting immediately before extraction.

Histologic examinations revealed the formation of 37 dentinbridges. The maximum and average thicknesses of the dentin bridgesare shown in Figure 3. Ca(OH)2, MTA, and Biodentine actively initiatedthe formation of reparative dentin in each tooth (n = 11), whereas Sin-gle Bond Universal was significantly less active and induced the forma-tion of 2 small (Fig. 4C) and 2 very small bridges (n = 4). At highmagnification, the reparative hard tissues in the CH and SBU groupshad an uneven thickness and exhibited porosities and tunnel defects(Figs. 2A2 and 4C), whereas those in the MTA and BIO groups werethicker and more homogeneous with minimal tunnel defects (Fig. 4Aand B). The thickness of the dentin bridges in the Ca(OH)2, MTA,and BIO groups was significantly greater than that in the SBU group,whereas there were no significant differences among the CH, MTA,and BIO groups There was no bacterial staining in any section.

CBCT ImagingThe average densities of young dentin, mature dentin, dentin

bridges, and pulp in the 4 groups are shown in Figure 5. Mature dentinhad the highest average density (2275.5) followed by young dentin(1714.0), dentin bridges (1179.1), and pulp (160.6). The largest dif-ference in density of the tissue was observed in young dentin and dentinbridges, whereas the smallest difference was observed in mature dentinand pulp.

The highest and lowest average densities of dentin bridges wererecorded in the MTA (1253.9) and SBU groups (1076.0), respectively,whereas the values in the CH and BIO groups were similar. However,statistically significant differences (Mann-Whitney U test) were observed

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Figure 2. Frontal reconstructed CBCT images showing the dentin bridge formed after direct pulp capping with calcium hydroxide (A, A1, and A2) histologicspecimens. (A) The dentin bridge contains particles of the material (H&E; original magnification, �50). (A1) The same image seen through the 38 HE(eGFP) filter. (A2) A higher magnification of A seen through the 43 HE (Cy 3) filter (original magnification,�400). (B) Measurement of densities and histogramsfor the pulp (1), dentin bridge (2), young dentin (3), and mature dentin (4). (C and D) Spatial model of a dentin bridge. (E and F) The same model presented inseveral planes. D, dentin; DB, dentin bridge; P, pulp; open arrowheads, tunnel defect.

Clinical Research

between the MTA and CH groups (P = .011). Particularly large differ-ences in density and structure were observed among the dentin bridgesformed in the CH and SBU groups (Figs. 2 and 4C).

Tomographic evaluations confirmed the presence of 25 bridgesout of the 37 identified by histology. The results for all specimens areprovided in Table 1 and Figures 1 and 4. The volume of reparative

Figure 3. The mean and maximal thickness values of dentin bridges in the 4groups.

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dentin formed was moderate in the Ca(OH)2 group and moderate tohigh in the MTA and BIO groups, with no significant differencesbetween the latter 2 groups. In the SBU group, only 2 bridges with asmall volume were identified. Reparative tissue with radiolucenttunnel defects is visible in Figure 4C. Significant differences in dentinbridge volume were observed between the CH, MTA, and BIO groupsand the SBU group (Table 1). Notably, the reparative dentin bridgesin the BIO group showed the highest average and maximum volumescompared with that in the other 3 groups (Table 2). Biodentine andMTA resulted in the formation of bridges with a significantly higheraverage volume compared with Single Bond Universal.

DiscussionTo our knowledge, the present study is the first to assess reparative

dentin formation using CBCT imaging in relation to the gold standard,which is histologic examination. CBCT images allow the acquisition of 3-dimensional images of dentin bridges and enable their qualitativeassessment (24, 26, 28). The results of our study showed thatCa(OH)2, MTA, Biodentine, and Single Bond Universal had differentdegrees of influence on dentin bridge formation, with the former 3positively affecting the exposed pulp and actively initiating theformation of reparative dentin in each tooth and the latter oneresulting in the formation of significantly lesser dentin bridges of a

Direct Pulp Capping with Ca(OH)2, MTA, and Biodentine 1237

Figure 4. Histologic images and spatial model of a dentin bridge after direct pulp capping with (A, A1, A2, and A3) MTA, (B, B1, B2, and B3) Biodentine, andSingle Bond Universal (C, C1, C2, and C3). (A–C) The dentin bridge (H&E; original magnification,�25). (A1, B1, and C1) Higher magnification seen through the38 HE (eGFP) filter (original magnification,�50). (A2, B2, and C2) Higher magnification seen through the 43 HE (Cy 3) filter (original magnification,�400). D,dentin; DB, dentin bridge; P, pulp. Open arrowhead indicates the tunnel defect.

Clinical Research

lower quality, thickness, and volume. Therefore, the null hypothesis thatthere is no difference in the quantity and quality of reparative dentinbridges formed after direct pulp capping with these differentmaterials in humans is rejected.

The disadvantage of CBCT imaging is a lower contrast and higherbackground noise (28, 29). Crown nodules, fillings, and denturesresult in artifacts on CBCT imaging in addition to local band beam-hardening artifacts of ‘‘cupping’’; therefore, it is necessary to definean algorithm to eliminate these artifacts (25). In our study, to eliminateartifacts from the CBCT images, each tooth was scanned separately.Furthermore, we used a standardized methodology to identify anddetermine the spatial structure of the dentin bridges. For best visualiza-tion of the dentin bridge, we used the parameters of width and windowlevel and ensured that the plane was compatible with that on the repre-sentative histologic section of the thickest dentin bridge. Dentin bridgeswith the highest average and maximum volumes were formed after theuse of Biodentine followed by the use of MTA, Ca(OH)2, and Single BondUniversal. Unfortunately, these results could not be compared withthose of other studies because of the lack of relevant literature.

Evaluation of tooth mineralization is crucial for understanding therepair and pathological processes occurring in the pulp. Although theCBCT diagnostics used in this study have sensitivity lower than that oflight microscopy, they can provide additional information on tertiarydentin mineralization (24, 26, 28). The authors observed regionswith different levels of mineralization on CBCT images, which is notpossible in demineralized histologic sections. Histograms were

1238 Nowicka et al.

plotted to facilitate data analysis and determine the distribution ofgray tones in the images, which helps in assessing the homogeneity ofthe structure and mineralization of the dentin bridge (28).

In previous studies (10, 30), micro–computed tomographicimages obtained 4 months after direct pulp capping with Ca(OH)2,MTA, and white Portland cement in baboons showed the presence oftissue resembling osteodentin, which was suggested by theresearchers to be the result of dystrophic calcification. Comparedwith these studies (10, 30), our study obtained better results interms of the quality of tissue repair. Ca(OH)2 induced the formationof a thick but very porous reparative dentin bridge (10). This porositymay facilitate the entry of bacteria into pulp (3, 11, 14). Particularlylarge variations in density were observed among the dentin bridgesformed in the SBU and CH groups. These variations, along with thosein the structure of the dentin bridges, can be attributed to the contentof particulate material in the reparative tissues, as observed in thehistologic sections. The particles of material present in the dentinbridge tissue can also affect the growth of density values. Micro–computed tomographic imaging, which was used in previous studies(10, 30), ensures a high-resolution and consistent phenotype and ismore accurate than CBCT imaging. Unfortunately, because of the highdoses of radiation, this modality cannot be used in in vivo studies (29).

The ability of Ca(OH)2, MTA, and Biodentine to induce the forma-tion of reparative dentin bridges in rat (14) and pig (15) pulp injurymodels was previously investigated. A significant difference wasobserved at 7 days after pulp capping between Biodentine and

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Figure 5. Mean values of the density for the mature dentin, young dentin, dentin bridge, and pulp in the 4 groups.

Clinical Research

Ca(OH)2 (15) although at 28 and 90 days there was no significant dif-ference between MTA, Biodentine, and Ca(OH)2 in terms of hard tissueformation, which is similar to the results of our study. The reparativetissues induced by MTA and Biodentine were homogenous, whereasthose induced by Ca(OH)2 were porous, suggesting a reparative processdifferent from that induced by calcium silicate (14, 31). Studies indicategreater tissue repair efficiency of calcium silicate compared with that ofCa(OH)2, probably because of the recruitment of pulp stem cells by theformer. These cells regulate the expression of transcription factors suchas RUNX2, which are involved in the process of moleculardentinogenesis (14, 32). Stimulation of cell proliferation anddifferentiation may be related to calcium silicate itself, which is oneof the main components of MTA and Biodentine (14, 16, 17, 33).Chang et al (31) observed a similar increase in alkaline phosphataseactivity, deposition of mineralized nodules, and up-regulation ofmarkers for odontoblastic differentiation in MTA and Biodentine.

Other researches (18, 34) after direct pulp capping in animalteeth noticed that Biodentine showed significantly higher stimulatoryactivity on pulp cells in comparison with MTA, resulting in thickerreparative dentin bridges and greater incidence of ectopic pulpcalcification in developing teeth. In our study, dentin bridges in theBiodentine group showed the highest maximum thickness andaverage and maximum volumes.

Application of Single Bond Universal elicited responses similar tothose observed with the use of bonding systems in humans (6, 9, 35).Despite the good seal and satisfactory biocompatibility, their ability toinduce dentin repair was significantly weaker than that of Ca(OH)2and calcium silicate–based materials (5, 6, 9, 35). In a previousstudy (5), MTA gave a more predictable, positive response in vitalpulp therapy compared with Ca(OH)2 and acid-etched dentin bondingsystems over longer time frames. Therefore, in consideration of the factthat bonding of resins to the underlying tissue deteriorates over time in

TABLE 1. Volumes of Reparative Dentin Bridges after Direct Pulp Capping with the

Volume of dentin bridgeCH* (n = 11),

n (%)MTA† (

n

No dentin (0) or unmeasurablevolume

4 (36.4) 3 (

Low volume 2 (18.2)Moderate volume 4 (36.4) 6 (High volume 1 (9.1) 2 (Total 11Pearson c2 test

BIO, Biodentine; CH, calcium hydroxide; MTA, mineral trioxide aggregate; SBU, Single Bond Universal.

*Spearman’s rank, P = .0119.†Spearman’s rank P = .0011.‡Spearman’s rank P = .0017.

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the absence of a dentin bridge, which increases the risk of pulp infec-tion, the use of these preparations on exposed pulp should be carefullyconsidered (36). In addition, the primer may continue etching thedentin for some time, causing an area of demineralization that is notfilled with the bonding system (37).

Some researchers, because of the lack of a correlation between thepresence of bacteria and the condition of the pulp, indicate that thetoxicity of the materials used could be a cause of the absence of dentinbridge formation (21). The components of bonding systems can becytotoxic to cells and microorganisms and can adversely affect the im-mune system and induce immunosuppression (38). In a recent study inhumans (7) in which Single Bond Universal was applied using the total-etch technique during the clinical procedure of direct pulp capping,light microscopy and scanning electron microscopy revealed subclini-cal adhesive failure as opposed to the satisfactory visual results. Resid-ual monomer, resin tags at the margins of the exposed pulp, and bloodand gaps between the adhesive layers were also observed (7). The re-sults of our study and those of previous studies confirm that materialssuch as MTA, Biodentine, and Ca(OH)2 are preferred over bonding sys-tems such as Single Bond Universal for direct pulp capping.

The present study was conducted under controlled experimentalconditions using third molar human teeth to avoid the interferenceby confounding factors. The fact that the teeth had healthy pulp tissuein all groups means that differences encountered in the pulp can beattributed exclusively to the capping material used. The intensity ofthe pulp reactions demonstrated in healthy teeth may be lower thanin carious teeth (39).

ConclusionIn conclusion, the volume of formed reparative dentin bridges de-

pends on thematerial used for direct pulp capping. Biodentine andMTA

4 Different Materials

n = 11),(%)

BIO‡ (n = 11),n (%)

SBU*,†,‡ (n = 11),n (%) Total

27.3) 3 (27.3) 9 (81.8) 19

0 1 (9.1) 2 (18.2) 554.6) 4 (36.4) 0 (0.0) 1418.2) 3 (27.3) 0 (0.0) 611 11 11 44

P = .0634

Direct Pulp Capping with Ca(OH)2, MTA, and Biodentine 1239

TABLE 2. Mean Volumes of Reparative Dentin Bridges Formed after Direct Pulp Capping in the 4 Groups

Group n Mean Median Minimum Maximum Q1 Q3 SD P value

CH 7 0.30 0.33 0.07 0.56 0.09 0.39 0.17 .4009MTA* 8 0.45 0.31 0.19 1.27 0.22 0.52 0.37BIO* 8 0.47 0.27 0.09 1.82 0.20 0.69 0.41SBU* 2 0.07 0.07 0.06 0.08 0.06 0.08 0.01

BIO, Biodentine; CH, calcium hydroxide; MTA, mineral trioxide aggregate MTA; Q1, first quartile (25th percentile); Q3, third quartile (75th percentile); SBU, Single Bond Universal; SD, standard deviation.

*Mann-Whitney U test, P < .05.

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induced the formation of bridges with a significantly higher average vol-ume compared with Single Bond Universal in this study, and CBCT im-aging allowed for the identification of the location of dentin bridges.Determination of the precise location and measurement of the volumeof dentin bridges on CBCT images is very difficult without correlationwith histologic findings because of certain limitations of CBCT imaging,such as a low contrast, background noise, and a small area of evaluatedtissue. Further studies using computed tomographic imaging and elec-tron microscopy are required for a more precise evaluation of repara-tive dentin bridges formed after direct pulp capping with variousmaterials.

AcknowledgmentsThe authors deny any conflicts of interest related to this study.

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JOE — Volume 41, Number 8, August 2015