|Year : 2015 | Volume
| Issue : 2 | Page : 104-110
Clinical and radiographic evaluation of indirect pulp treatment with MTA and calcium hydroxide in primary teeth (in-vivo study)
Vimi George, Suresh Kumar Janardhanan, Balagopal Varma, Parvathy Kumaran, Arun Mamachan Xavier
Department of Pedodontics and Preventive Dentistry, Amrita School of Dentistry, Cochin, Kerala, India
|Date of Web Publication||15-Apr-2015|
Dr. Balagopal Varma
Department of Pedodontics and Preventive Dentistry, Amrita School of Dentistry, Amrita Institute of Medical Sciences, P.O- Ponekkara, Cochin - 682 041, Kerala
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objectives: Clinical and radiographic effects of mineral trioxide aggregate (white MTA) and calcium hydroxide (Dycal) in indirect pulp treatment (IPT) of primary teeth over a period of 6 months. Materials and Methods: A clinical trial with sample size of 40 primary molars between the age group of 5-9 years, of which, 20 teeth were considered, each for MTA and Dycal. Measurements on the digitized radiographs were performed at baseline, third and sixth month, increase in dentin was then measured using Corel Draw software. Result: Independent t-test had indicated that at the end of 3 months and 6 months, a statistically significant increase in dentin thickness with both MTA and Dycal (P-value ≤ 0.001) was found. Within the MTA group, the thickness of dentin formed was 0.089 mm ± 0.031 mm at first 3 months and 0.055 ± 0.022 mm at the second 3 months, (P ≤ 0.001) evaluated using paired t-test. In the Dycal group, increment in dentin deposited was 0.068 mm at the first 3 months and second 3 months, it was 0.030 mm (P-value ≤ 0.001). Conclusion: Clinically and radiographically, MTA is superior to Dycal as a good IPT medicament in primary teeth.
Keywords: Dycal, indirect pulp treatment, mineral trioxide aggregate, primary teeth, reactionary dentin
|How to cite this article:|
George V, Janardhanan SK, Varma B, Kumaran P, Xavier AM. Clinical and radiographic evaluation of indirect pulp treatment with MTA and calcium hydroxide in primary teeth (in-vivo study). J Indian Soc Pedod Prev Dent 2015;33:104-10
|How to cite this URL:|
George V, Janardhanan SK, Varma B, Kumaran P, Xavier AM. Clinical and radiographic evaluation of indirect pulp treatment with MTA and calcium hydroxide in primary teeth (in-vivo study). J Indian Soc Pedod Prev Dent [serial online] 2015 [cited 2019 Nov 13];33:104-10. Available from: http://www.jisppd.com/text.asp?2015/33/2/104/155118
| Introduction|| |
Indirect pulp treatment (IPT) of primary teeth has gained increased worldwide popularity in recent years and has shown to have a lower cost, higher long-term success, better exfoliation pattern, and better success treating reversible pulpitis than pulpotomy. 
Indirect pulp capping involves the removal of softened infected dentin leaving behind an intact layer of dentin, followed by application of indirect pulp capping agent and restoration. Edwina A.M. Kidd stated in an article that if the biofilm at the tooth surface drives the caries lesion, all that must be removed to arrest the lesion is the biofilm. Supposing a clinician disagrees with this interpretation and wishes to remove all the infected dentin, can this be achieved? The answer to this question is that it is not possible. Shovelton's review of 1968 showed that softening of dentin generally precedes the organisms responsible for it, but a few organisms will remain even if all the soft dentin is removed. 
During cavity preparation all soft dentin had been removed until a hard solid base was reached. Careful visual inspection along with tactile sensation had helped in removing the soft dentin. Caries detector dyes were not used as it had been demonstrated that absence of stain does not ensure elimination of bacteria.  It is clearly established that these dyes do not stain bacteria but instead stain the organic matrix of less mineralized dentin.  The lack of specificity of caries-detector dyes was confirmed in 1994 by Yip and others.  They correlated the location of dye-stainable dentin with mineral density. The dyes neither stained bacteria nor delineated the bacterial front but did stain collagen associated with less mineralized organic matrix. Of even greater significance was the fact that when these authors utilized the dyes on caries-free, freshly extracted human primary and permanent teeth, they discovered that sound circumpulpal dentin and sound dentin at the amelo-dentinal junction took up the stain because of the higher proportion of organic matrix normally present in these sites. Clearly, the routine use of these dyes without an understanding of their distinct limitations will result in excessive removal of totally sound tooth structure and increased likelihood of mechanical pulp exposures.
Indirect pulp treatment (IPT) is an age-old procedure and historically calcium hydroxide (Dycal) had been a gold standard for pulp capping following the initial publication of Zander  in 1939. The unfavorable effects of Dycal like internal resorption, degradation over time, tunnel defects through dentinal bridges under it, and poor sealing properties  had resulted in failures of the treatment. So, favor for this conservative treatment approach had declined over the course of time. Alternatively, pulpotomy which had a much aggressive approach had come into common practice. But with the advent of newer materials like MTA, this scenario has changed. MTA which is a pulp sealing agent essentially composed of a mixture of tricalcium silicate, dicalcium silicate, tetracalcium aluminoferrite, and calcium sulphate dehydrate with an addition of bismuth oxide in a 4:1 ratio  had been shown to be an effective pulp capping material in canine models and in non-human primates.
The material appeared to be successful because of its small particle size, sealing ability, alkaline pH when set, sets in presence of moisture and its slow release of calcium ions. MTA induces pulp cell proliferation, cytokine release, and subsequent hard tissue formation with the synthesis of a mineralized dentin similar to that of biological hydroxyapatite.  Due to these, superior properties of newer materials like MTA had led on to the re-emergence of
There are many studies evaluating the effect of Dycal for IPT in permanent and primary teeth and few case reports and clinical studies have evaluated the effect of MTA for IPT in permanent teeth. On electronic literature search of scientific papers using MEDLINE, Embase, Entrez, Pubmed, and Scopus databases, we found that no studies have been conducted to evaluate the effect of MTA in primary teeth IPT.
The above disclosed fact prompted us to undertake this clinical study in our Department at Amrita School of Dentistry, Cochin.
This study aimed to assess the effectiveness of mineral trioxide aggregate (MTA) compared to Dycal in IPT of primary teeth and radiographic comparison of thickness of dentin bridge formed by MTA, and Dycal using a novel software.
| Materials and Methods|| |
The study design was a clinical trial in a sample of forty primary molars.
Primary molars were selected from patients aged 5-9 years attending the OP of the Department of Pedodontics & Preventive Dentistry in Amrita School of Dentistry, Cochin. A total of 40 teeth were considered out of which twenty teeth were considered for each material group.
- History of tolerable dull intermittent pain, mild discomfort associated with eating, negative history of spontaneous extreme pain.
- On clinical examination, large carious lesions involving either the occlusal or proximal surfaces, with normal appearances of gingiva.
- Radiographic examination revealed carious lesion involving more than 2/3 rd thickness of dentin approximating the pulp, normal lamina dura, normal periodontal ligament space, more than 2/3 rd of root present, no periapical changes, no pathologic external or internal resorption, should not cause any harm to the succedaneous tooth.
- History of sharp, penetrating pulpalgia indicating acute pulpal inflammation and necrosis, prolonged spontaneous pain at night.
- Clinical examination revealed presence of mobility of tooth, discoloration of tooth, negative reaction to electric pulp testing, sinus opening, or abscessed tooth.
- Radiographic examination revealed carious lesion producing definite pulp exposure, interrupted or broken lamina dura, widened periodontal ligament space, periapical radiolucency, internal or external resorption.
The present study had been approved by the ethical committee of Amrita School of Dentistry, Cochin, Kerala. Patient's parents were informed about the procedure and provided written consent both in English and Malayalam.
Local anesthesia was administered following which rubber dam was applied and the carious lesion was removed [Figure 1].
Following caries removal, MTA powder mixed with sterile water for 30 seconds so as to get a sandy consistency, carried with a ball ended condenser tip and applied by light pressure with moist cotton pellet and temporized. The permanent Glass Ionomer Cement (GIC) filling was done subsequently [Figure 2].
In the control group, Dycal was mixed with equal quantities of both the catalyst and the base paste to a homogenous paste. This was applied to the sites with ball ended condenser [Figure 2]. In both the experimental and control group, cavities were restored with GIC during the 6 months evaluation period [Figure 3].
Immediately, a baseline radiograph with grid was made with a XCP-holder. Subsequently, at third and six months, the tooth were clinically examined and radiographically evaluated by taking X-rays. Clinical evaluation was done for pain, tenderness to percussion, discoloration of teeth, and presence of sinuses.
All the radiographs were subsequently scanned and transferred to the computer for digital analysis. Measurements on the digitized radiographs were performed at baseline, third, and sixth month. The increase in dentin thickness was thus measured using Corel Draw software, Version 13 [Figure 4], [Figure 5], [Figure 6], [Figure 7].
On each digitized radiograph, evaluation was done for root resorption, widening of periodontal ligament (PDL) space, periapical radiolucency, dentin formation, and any intra pulpal calcifications. Treatment was considered to be successful when the pulp remained vital with a normal response without signs of spontaneous pain.
Radiographically, treatment was considered successful when reactionary dentin was present over the lesion with no furcation radiolucency, PDL space widening, internal and external root resorption. Stainless steel crowns were advised after the evaluation period of the study. The data obtained were analyzed using the Independent t-test for intergroup analysis and paired t-test for intra-group analysis.
| Results|| |
Purpose of this study was to compare the clinical and radiographic effects of MTA and Dycal in primary teeth IPT after 6 months. Total of 20 specimens were included in MTA group, of which one specimen was excluded during the study due to loss of restoration. Readings of remaining nineteen specimens were recorded. Similar to the MTA group, total of 20 specimens were included in Dycal group, of which one specimen was excluded due to loss of restoration and three were lost to follow-up during the 3 months follow-up. At 6 months follow-up, one failed due to development of sinus discharge and the remaining fifteen specimens were recorded for the study [Table 1].
For inter-group analysis, an independent t-test had been performed which suggested that at the end of 3 and 6 months, there is a statistically significant increase in dentin thickness with both MTA and the Dycal with a P value ≤ 0.001, respectively [Table 2]. The success of the material is accounted on behalf of its capacity to induce dentin deposition, i.e., difference in the amount of dentin deposited at the end of 3 and 6 months. The difference in the amount of dentin deposited at the end of 3 and 6 months, [Table 3] indicated that the mean dentin deposited in MTA group at 3months was 0.089 mm, whereas in Dycal group it was 0.068 mm (P value 0.038) signifying that MTA is superior to Dycal.
At the end of 6 months, in MTA group tertiary dentin deposition was 0.143 mm of dentin and Dycal group, dentin deposit was 0.097 mm which were also statistically significant with a P-value of 0.004 [Table 4]. From these observations, we could conclude the fact that MTA was superior to Dycal at the end of both 3 and 6 months.
|Table 4: Increment in dentin deposited at first 3 and the second 3 months|
Click here to view
Within the MTA group, the thickness of dentin formed was 0.089 mm ± 0.031 mm at first 3 months and 0.055 ± 0.022 mm at the second 3 months, with a P ≤ 0.001 indicating that dentin deposition in MTA group is more at the first 3 months than with the next 3 months. This was evaluated using a paired t test [Table 4]. In the Dycal group too, amount of dentin formed at 3 and 6 months was statistically significant. Increment in dentin deposited was 0.068 mm which was more at the first 3 months than the second three months which was 0.030 mm with a P-value ≤ 0.001, but the rate was more with MTA than Dycal.
[Figure 8] depicts that MTA deposited more dentin than Dycal at the end of 6 months.
[Figure 9] represents that the increment of dentin formed at the first 3 months is more than that formed at the second 3 months in both the MTA and Dycal group. Dentin deposited at first 3 months and second 3 months is more with MTA than that compared with Dycal.
|Figure 9: Increment of dentin deposited at first 3 months and second 3 months|
Click here to view
| Discussion|| |
The authors such as Farooq et al.  in 2000, Al-Zayer et al.  in 2003, and Vij et al.  in 2004 had proved that the success of IPT was more than with the formocresol pulpotomy technique. Farooq et al.  exhibited that primary molars treated with formocresol pulpotomy had exfoliated earlier whereas indirect pulp treated molars exhibited normal exfoliation.
Most recently introduced material MTA, is available as gray MTA (GMTA) and white MTA (WMTA). It appears that MTA seals the pathways of communication between the root canal system and the external surfaces of the teeth. Therefore, it is suitable as a pulp capping material during vital pulp therapy.  The WMTA and GMTA differs mainly in their content of iron, aluminium, and magnesium oxides. Asgary et al.  claim that these oxides are present in less quantity in white MTA. WMTA, when compared with GMTA, contains smaller particles with a narrower range of size distribution.  Based on the study by Ali Eskandarizadeh  in 2011, both types of GMTA and WMTA can be suggested as the material of choice for pulp capping and no significant difference was found between them in terms of calcified bridge formation and thickness as well as pulpal inflammatory response.
On clinical examination, one patient had reported with sinus opening during the course of follow-up of the study with no cases of radiographic failure in the Dycal group. No cases with clinical and radiographic failure had been reported in the MTA group. In a 2-year randomized clinical trial with Dycal and MTA in direct pulp capping of permanent teeth, Hilton et al.  in 2013 had provided confirmatory evidence on the superior performance of MTA. MTA was found to be as successful as Dycal when used for direct pulp capping in primary teeth in a long term clinical evaluation by Tuna et al.  in 2008. Dycal possesses antibacterial properties, and this can minimize or eliminate bacterial penetration to the pulp. Dycal's high pH causes irritation of the pulp tissue, which stimulates repair which is explained by the release of bioactive molecules. It is known that a variety of proteins are incorporated into the dentin matrix during dentinogenesis. Bone Morphogenic Protein (BMP) and Transforming Growth Factor-Beta One (TBF-β1), have demonstrated the ability to stimulate pulp repair.
Dycal is known to solubilize these proteins from dentin, lending credence to the release of these bioactive molecules as a significant mediator in pulp repair following pulp capping.  Unset MTA is primarily calcium oxide in the form of tricalcium silicate, dicalcium silicate and tricalcium aluminate. Interestingly, the primary reaction product of MTA with water is Dycal, and so it is actually the formation of Dycal that provides MTA's biocompatibility. As a result, many of the advantages and potential mechanisms of action for MTA are similar to Dycal, including its anti-bacterial and biocompatibility properties, high pH, radiopacity, and its ability to aid in the release of bioactive dentin matrix proteins. MTA is capable of maintaining high pH in the range between 11 and 12. The high pH of MTA could be of clinical significance as alkalinity creates a favorable environment for cell division and matrix formation. , With regards to the assessment of dentin thickness, the average reactionary dentin deposition following IPT in primary teeth with MTA in this study is 0.143 mm at 6 months and 0.097 mm at 6 months in the Dycal group. In the study by Leye Benoist et al.,  average dentin thickness in IPT in permanent teeth with MTA was 0.235 mm at 6 months and 0.221 mm with Dycal. The average thickness of dentin is almost 2 times lower with MTA in this study than that estimated by Leye Benoist. There may be various reasons for the differing dentin thicknesses. One of the differences may be the difference in permeability in the dentinal tubules of primary and permanent teeth. The density and diameter of the dentinal tubules in primary molars were found to be lower than the permanent teeth. The smaller density and diameter may account for the lower permeability of the primary than the permanent teeth. 
Aeinehchi et al.  reported that Dycal is associated with tissue necrosis and inflammation during the initial period of placement but no such inflammation or necrosis was seen in the pulp tissue adjacent to MTA. He reported a 0.28 mm thick dentin bridge by 2 months which increased to 0.43 mm by 6 months. The dentin bridge formed with Dycal was only 0.15 mm by 6 months. This difference in dentin thickness with both MTA and Dycal could be related to direct or indirect capping procedure. In addition, our measurements were made radiographically at baseline, 3 and 6 months, whereas histological cuts of dentine formation were measured. However, the results of Aeinehchi et al., is also similar to our result, that is, MTA is superior to Dycal.
The bioavailability of calcium (Ca) ions plays a key role in the various biological events on cells involved in the new formation of mineralized hard tissues. Ca ions stimulate the expression of bone-associated proteins mediated by calcium channels and large quantities of Ca ions could activate adenosine triphosphate (ATP), which plays a significant role in the mineralization process.  MTA's success is likely due to the fact that it serves as a reservoir for Dycal. Takita et al.  in 2006 showed that calcium ion concentration increased approximately 0.3 mmol /L in the MTA and essentially did not change in Dycal. It proved that the elution components such as calcium ions from MTA had higher proliferation ability of human dental pulp cells than Dycal. In a study by Maria Giovanna GandolfI in 2012 evaluating the diffusion of Ca 2+ and OH - Ions through coronal dentin into the pulp using different pulp capping agents, it was found that these ions diffuse effectively even at remaining dentin thickness (RDT) thicknesses of 1.0 ± 0.2 mm.  According to Koutsi et al., the permeability of both primary and permanent teeth increased with increasing dentin depth (or reductions in remaining dentin thickness), meaning that permeability decreases with increased thickness. 
In this study, we found a faster formation of the dentine bridge at the first 3 months in the MTA group than in the Dycal group. This could be explained by the fact that MTA serves as a reservoir for Dycal and the calcium release from MTA materials decreases slightly over time.  MTA released significantly more calcium ions than Dycal throughout the experimental period. ,
Following a pulp treatment procedure, bacterial leakage through the final restoration is considered to be more detrimental to outcome than bacterial contamination at the time of the treatment. This finding underlines the need for a good seal in the final restoration after the completion of the pulp treatment. It has been shown that glass-ionomer cement layered over the setting MTA does not affect further setting of MTA, and although the calcium salts may be formed at the interface, they were restricted to the interface only. As suggested by Nandini et al.,  GIC restoration was placed over the pulp capping medicament in our study.
| Conclusion|| |
Based on the results of this short-term clinical and radiographic study, following conclusions were drawn:
- Clinically both MTA and Dycal are good IPT medicaments in primary teeth.
- Radiographically, MTA is superior to Dycal as IPT medicament in primary teeth.
- Dentin deposition is more when MTA is used than Dycal after 3 and 6 months.
- Dentin deposition is more in first 3 months than second 3 months for both MTA and Dycal.
However, further research with larger samples and a longer follow up is warranted. Additional histological investigations are needed to support these findings.
Importance of the study
This study suggests that MTA is superior to Dycal as a medicament for IPT in primary teeth. So we believe that the excellent results found with MTA allow its recommendation for IPT in primary teeth which maintains the vitality of the teeth with minimum discomfort to children.
| Acknowledgement|| |
The authors are grateful to the faculty and the post graduates of Department of Pedodontics and Preventive Dentistry and the Dept. Of Biostatistics for their valuable support towards this clinical research.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]
[Table 1], [Table 2], [Table 3], [Table 4]