Comparative evaluation of different direct pulp capping agents in carious tooth: An in vivo study.

BACKGROUND: The success of direct pulp capping (DPC) depends on the preoperative assessment of pulpal status, intraoperative judgment after pulp exposure, and the biomaterials used to cap the pulp. AIM: The study aims to compare the clinical and radiographic responses of the pulp-dentin complex after DPC with TheraCal LC, Biodentine, and current gold standard mineral trioxide aggregate (MTA) Plus.
MATERIALS AND METHODS: Ninety vital permanent teeth with Class I deep carious lesions were randomly divided into three different groups. After the caries excavation, hemostasis was established using sodium hypochlorite at the site of pulp exposure on which the material was placed. Clinical and radiographic follow-ups were performed at 1-, 3-, and 6-month intervals.
RESULTS: Overall success rates of MTA Plus, Biodentine, and TheraCal LC were statistically insignificant.
CONCLUSIONS: TheraCal LC and Biodentine showed similar success rates when compared to MTA Plus and can be used as an agent in DPC. Copyright:

INTRODUCTION

Any healthy pulp tissue has an innate capacity to repair. The pulp can heal even after carious exposure if the inflammation is suggestive of reversible pulpitis.[1] The treatment option for a pulpal exposure in a tooth includes direct pulp capping (DPC), pulpotomy, and pulpectomy. DPC is defined as “placing a dental material such as calcium hydroxide directly on a mechanical or traumatic vital pulp exposure,”[2] however, a review[3] and a cost-effective analysis[4] yielded evidence that vital permanent teeth with carious pulp exposures can be managed successfully with DPC. With the advent of hydraulic calcium silicate cement, vital pulp therapy (VPT) has become more predictable. The study aimed to compare and assess the success rates of DPC with these three materials by evaluating the vitality of the pulp by using thermal, electric pulp tests and visualize the formation of reparative dentin using radiographs. This brings a change in the thought process of readily performing root canal treatment wherein the concerns of overtreatment are existent when the pulp is cariously exposed.

MATERIALS AND METHODS

Ethical clearance and sample size determination

This is a prospective, single-center, single-blinded randomized controlled clinical trial. The study was conducted at the department of conservative dentistry and endodontics. The study protocol was approved by the institutional ethics committee and followed the CONSORT guidelines (http://www.consort-statement.org) perspicaciously [Chart 1].

Chart 1

Consort chart Number of patients in each group

All subjects were treated according to the Helsinki Declaration. Based on a similar study conducted by Nowicka et al.,[5] sample size of 90 (n = 30 per group) was estimated using the G*Power 3.1.9.7 package with 0.80 power and P ≤ 0.05 and dropout rate of 20%. The patients who reported to the department of conservative dentistry and endodontics over a period of 16 months starting December 2016 were screened to determine whether patients fulfilled the inclusion criteria. After screening, ninety patients within the age group of 15–45 years were deemed fit for the trial.

Written informed consent was obtained from the patients involved in the clinical trial, after a detailed explanation of the rationale, clinical procedure, and potential risks associated with the study. The teeth were randomized and allocated to one of the three groups. Group I: TheraCal LC (Bisco, USA), Group II: Biodentine (Septodont, France), and Group III: mineral trioxide aggregate (MTA) Plus (Prevest Ltd., Jammu, India). Randomization was performed using the envelope method. The patients were blinded to the groups of materials used. Blinding of the single operator and data analyst was not possible in this type of clinical trial, making this a single-blinded study.

Methods

Inclusion criteria were preoperative presence of a deep carious lesion, systemically healthy co-operative patient, permanent molars with carious lesions restricted to the occlusal surface, positive response to thermal and electric pulp tests, sensitivity to cold food and/or food lodgment, and no radiographic evidence of periapical pathology. Exclusion criteria were continuous or spontaneous pain, presence of a swelling or a sinus tract adjacent to the tooth, tenderness on percussion, pathologic tooth mobility, excessive hemorrhage from exposure site indicating progressive inflammation or requiring pulpotomy, radiolucency in periapical or furcation area, external or internal resorption, and obliteration of canal.

After thorough history indicating reversible pulpitis, the sensibility tests were performed using ROEKO Endo-Frost (Coltene, Whaledent®) and Gentle Pulp Tester (Parkell, USA).[6] Intraoral periapical radiographs were taken with the position indicating device. The tooth was isolated with a rubber dam (Hygienic; Coltene, Switzerland) after administering local anesthesia (2% lignocaine with 1:80,000 adrenaline). Nonselective caries excavation was performed from the periphery towards the center with round bur (BR 31, Mani, Japan). After approximating near the pulp, a sharp spoon excavator (Dentsply B190) was used for the removal of residual carries under the magnification loupes (×3.5). A new cassette set of sterile instruments were used at this point to minimize the contamination caused by carious debris from instruments to the exposed site and the capping material. Bleeding was controlled by placing a sterile cotton pellet moistened with 3% sodium hypochlorite for 5 min. The tooth was rinsed with saline to remove excess sodium hypochlorite. If hemostasis was not achieved within 5 min, the tooth was excluded from the study.[7] TheraCal LC, Biodentine, and MTA Plus were prepared according to the manufacturer's instructions. Selective enamel etching was done (N-Etch, Ivoclar Vivadent, India). Tooth was restored with composite (Tetric N-Ceram and Tetric N-Bond Self-Etch, Ivoclar Vivadent, India) restoration in the same sitting with TheraCal LC. Interim restoration with Orafil G (Prevest Denpro, Jammu and Kashmir, India) was placed after MTA and Biodentine, and patients were recalled for permanent composite restoration (Tetric N-Ceram and Tetric N-Bond Self-Etch, Ivoclar Vivadent, India) after 3 and 7 days, respectively [Figure 1].

Figure 1

Representative images of the tooth: (a-c) After caries excavation and (d-f) Capped with Biodentine, mineral trioxide aggregate Plus, and TheraCal LC, respectively, (g-i) By composite restorations

Recall

The patients were recalled for clinical and radiographic evaluation after 1-, 3-, and 6-month intervals. No adverse events were reported during treatment and follow-up. History of spontaneous/night pain after the treatment, sensibility status of teeth, discoloration of teeth and restoration, surface texture, anatomic form, secondary caries, postoperative sensitivity, marginal discoloration and marginal integrity of the restoration, radiographic signs of periapical pathology, calcification of pulp chamber, and dentin bridge formation were assessed. Teeth that remained asymptomatic, positive response similar to adjacent and contralateral tooth with thermal tests and Electric pulptest (EPT) and no radiographic signs of periapical pathology were considered successful. CorelDRAW X7 Software (corel corporation, ontario, canada) overlapped 1st- and 6th-month radiographs. Qualitative assessment of the radiograph was done to find whether the reparative dentin is visible or not. Radiographs were adjusted in the software to fit in the measurement of 41 mm ×31 mm. Radiographs were digitized with fixed magnification ratio in camera to avoid photographic error. The transparency of overlapped radiographs was adjusted to view both radiographs simultaneously one above the other so that differences in both radiographs at the level of material placement could be appreciated [Figure 2]. The overall success rates between groups and at each time interval were compared using the Chi-square test.

Figure 2

Representative image of (a) Preoperative radiograph, (b) One-month follow-up, and (c) Six months follow-up. (d) Overlapped radiographs in the software

RESULTS

Results tabulated are based on the success and failure rates of the materials used. The following numbers of patients were excluded from the study during analysis:

Group I – TheraCal LC: two patients; one reported a severe history of night pain at 4 months and the other with tenderness on percussion and delayed response at 6-month intervals, respectively. Group II – Biodentine: three patients; the first patient reported after a 3-month follow-up. The patient was asymptomatic, but tooth became nonvital. The second and third patients reported back within 2- and 6-month intervals, respectively, with a history of severe nocturnal pain. Group III – MTA Plus: two patients; one with a complaint of nocturnal pain, 1.1/2 months after the treatment, and the other at 3-month period. Vitality tests were performed and teeth were diagnosed with irreversible pulpitis. Total seven cases were evaluated as a failure and ten patients were lost to follow-up. Success rate with TheraCal LC, Biodentine, and MTA as a DPC agent was found to be Group I – 92.59%, Group II – 88.88%, and Group III – 92.30% [Table 1]. The results were statistically insignificant.

Table 1

Success and failure rates according to material used

According to materials used
	TheraCal LC	Biodentine	MTA Plus	Total	P
Success	25	24	24	73	0.9739
Failure	2	3	2	7
Total	27	27	26	80

MTA: Mineral trioxide aggregate

DISCUSSION

The demographics and baseline clinical characteristics of the subjects were evaluated to assess the comparability between all the groups. Age, sex, and reparative dentin formation were comparable between the groups [Table 2].

Table 2

Comparison of baseline data and demographic findings

Variable	TheraCal LC	Biodentine	MTA Plus
Age
15-25	14	14	13
26-35	8	8	7
36-45	5	5	6
Gender
Female	15	16	16
Male	11	11	11
Dentin bridge
Not visible	7	4	10
Visible	18	20	14

MTA: Mineral trioxide aggregate

VPT is scarcely practiced in cariously exposed pulp due to the difficulty in clinically assessing the level of inflammation and bacterial contamination and determining the healing potential of the pulp tissue. Accurate diagnosis of reversible pulpitis with detailed pain history, meticulous clinical examination supplemented with a periapical radiograph, and pulp sensibility tests by cold testing and EPT are important. Sterile and aseptic environment, magnification, time in which hemostasis is attained, and placement of dentin simulating biomaterial are other factors to be strictly considered.

Traditional materials like calcium hydroxide lack the ability to form a satisfactory barrier.[8] New bioceramic materials induce predictable hard tissue barrier formation,[69] and surface seal[10] offers new opportunities for DPC procedures in the tooth with carious exposure. They also possess the ability to induce the release of dentin matrix components which boosts chemotaxis, angiogenesis, and the differentiation of progenitor cells into dentinogenic cells.[11]

All the three materials used in this study are calcium silicate-based materials. The major composition difference between the three materials is that MTA Plus has a smaller particle size than conventional MTA. It has water-soluble polymers in its liquid that increases the calcium releasing ability but has increased solubility and setting time. Biodentine has calcium chloride in its liquid which decreases the setting time, increases the calcium releasing ability, and reduces the solubility. It requires an amalgam vibrator for its preparation which prevents the clinician from adjusting the fluidity of the paste or regulating the amount of mixing liquid. Hence, TheraCal LC which has a resin component (polyethylene glycol dimethacrylate) was also considered in the study due to its immediate setting, ease of dispensing, and usage. It had low solubility, but the ability to release calcium ions was less than the other two materials used in the study.[12] TheraCal LC provided higher shear bond strength as compared to Biodentine.[13]

Studies which compared treatment outcome using bioceramic materials in mature permanent teeth with carious exposure found that there was no statistically significant difference in success rates with respect to the materials used, which support the results of the study.[14] Gopika et al.[15] compared and evaluated the response of the human pulp following DPC and found that TheraCal LC and Septocal LC (calcium hydroxide with hydroxyapatite) cement were as effective as Dycal in the formation of reparative dentin. Studies also suggest that bioactivity of TheraCal LC is considerable though it has the presence of silanol and resin groups since they could promote the nucleation of calcium phosphate deposits. This factor attributes the success of DPC.[12] Contradictory results have also been reported where TheraCal LC has shown a decrease in success rates over a long-term follow-up of 36 months due to cytotoxic effect of unpolymerized resin monomers as compared to MTA Plus and Biodentine.[16] More in vivo studies on carious tooth are needed to evaluate this.

A new technique for assessing dentin bridge formation digitally using CorelDRAW X7 software has been established. Minimal errors are possible during overlapping in the software, but stringent efforts were made to minimize the error by confirming the maximum precision of the software. No cases of pulp obliteration were diagnosed in our study. This is promising because pulpal calcification is associated with the need for conventional root canal therapy. The study had a short-term follow-up of 6 months. However, a longer follow-up period is needed to fully analyze this aspect. Class I restorations were evaluated in the study, but success rates in proximal caries and its restoration also need to be assessed. EPT and cold test were used to test the pulp sensibility during follow-up. Future studies should emphasize on chairside, less cumbersome, more accurate, repeatable, reproducible, and economical methods to diagnose the actual status of the pulp during follow-up.

CONCLUSIONS

Within the limitations of the study, it can be concluded that TheraCal LC, Biodentine, and MTA are potential DPC agents as statistically there was no significant difference between their performances individually. More predictable ways to diagnose the pulpal status preoperatively as well as after exposure at a molecular level form as a basis for further research. The future scope for this study involves the assessment of dental pulp stem cells with newer pulp capping materials such as Emdogain, propolis, and nanohydroxyapatite to form a natural dentin-pulp complex.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.