ORIGINAL RESEARCH

https://doi.org/10.5005/jp-journals-10077-3247
Journal of South Asian Association of Pediatric Dentistry
Volume 5 | Issue 3 | Year 2022

Efficacy of Papain Gel—A Smart Alternative to Conventional Methods of Carious Dentin Removal: An In Vitro Study

Paras Angrish¹ https://orcid.org/0000-0003-0721-0353, Ashish Kamboj² https://orcid.org/0000-0002-1836-6786, Malay Mitra³, Rahul Kaul⁴, Dempsy MM Chengappa⁵ https://orcid.org/0000-0002-5014-7030, Aarti Sharma⁶

¹Department of Pedodontics and Preventive Dentistry, Dr R Ahmed Dental College and Hospital, Kolkata, West Bengal, India

²Department of Orthodontist, Army Dental Corps, India

³Department of Paediatric and Preventive Dentistry, Guru Nanak Institute of Dental Sciences, Kolkata, West Bengal, India

⁴Department of Pediatric Dentistry, Army Dental Corps, Imphal, Manipur, India

⁵Department of Pediatric and Preventive Dentistry, Dental, INHS Sanjivani, Kochi, Kerala, India

⁶Medical Data Reviewer Specialist II, Labcorps, Bengaluru, Karnataka, India

Corresponding Author: Paras Angrish, Department of Pedodontics and Preventive Dentistry, Dr R Ahmed Dental College and Hospital, Kolkata, West Bengal, India, Phone: +91 9051813036, e-mail: drparasangrish@gmail.com

Received on: 17 October 2022; Accepted on: 29 November 2022; Published on: 26 December 2022

ABSTRACT

Aim: The study was aimed at finding out the efficacy of the caries removal ability of a chemomechanical agent (papain gel) and comparing it with that of conventional slow-speed rotary carbide burs and mechanical hand excavators in deciduous extracted molars.

Materials and methods: A total of 30 extracted teeth that were used for the present study were distributed equally among two major categories (15 each) by simple random sampling technique. The teeth were sectioned into two halves mesiodistally in a longitudinal plane through the center of the caries.

In each category, the corresponding halves were sectioned off randomly but in equal numbers further into two groups as follows:

Category 1: Group I hand excavators and group II carbide burs.

Category 2: Group III hand excavator group and group IV Papacarie group.

Parameters recorded included total time taken for caries removal and residual caries remaining using caries detection dye in each group and category, which were estimated and observed under a stereomicroscope (magnification 12.5×). The data was computed and statistically analyzed to find out and compare the efficacy of caries removal of three different methods used.

Results: As per the critical difference (CD), the results of the study showed the caries removal mean time for group IV (Papacarie group) when compared to other groups was significantly higher (p < 0.01). Group II had a significantly lower mean time than the other groups (p < 0.01). Results also showed group II had a significantly lower mean area of residual caries than the other groups (p < 0.01). A significantly lower mean of residual caries was found in group IV than that in group I and group III (p < 0.05).

Conclusion: From the results of this study, it was found that papain gel can be used as an effective alternative method compared to conventional methods for caries removal, especially in pediatric patients, owing to its lesser time commitment and better outcome.

How to cite this article: Angrish P, Kamboj A, Mitra M, et al. Efficacy of Papain Gel—A Smart Alternative to Conventional Methods of Carious Dentin Removal: An In Vitro Study. J South Asian Assoc Pediatr Dent 2022;5(3):152-156.

Source of support: Nil

Conflict of interest: None

Keywords: Chemomechanical, Conventional caries removal, Papacarie, Papain gel

INTRODUCTION

The fundamentals of minimally invasive dentistry are remarkably based on minimal loss of sound enamel and dentin methods of caries removal.¹ Therefore, operative treatment for caries removal is currently conceptualized as arresting the progression of the lesion and providing a sound restorative foundation by removing only infected soft tissue.²

The mechanical rotary instrument approach to caries removal is not fundamentally conservative, as these instruments are designed for the efficient removal of non-decalcified enamel and dentin but do not readily differentiate between carious and normal dentin. The possible extension into the healthy dentin may be accompanied by pain, which hence requires local anesthesia during treatment and is associated with higher chances of pulp damage.³

As bacteria are not found in the advancing front of the carious lesion, removing the complete carious lesion of dentin is not necessary. Carious dentin can be either affected or infected. Soft, demineralized, and not invaded by bacteria is known as “affected” dentin and is not required to be removed. Whereas, outer carious dentin, which is soft, demineralized, and invaded by bacteria, is infected dentin and can be selectively stained by caries detection dye, such as 1% acid red (acid rhodamine B of food red 106) in propylene glycol, as stated by Fusayama in 1979.⁴

Chemomechanical caries excavation is an excellent example of a conservative caries removal method due to its ability to reliably preserve a greater thickness of caries-affected dentin.⁵ Chemomechanical caries removal (CMCR) agents are classified into sodium hypochlorite (NaOCl)-based agents and enzyme-based CMCR agents. Currently, the Carisolv gel (Medi Team Dentalutveckling AB, Göteborg, Sweden an improved variety of NaOCl-based chemomechanical agents,⁶ which chlorinates and disrupts hydrogen bonds of partially degraded collagen in carious dentin, thereby facilitating its removal, is considered the gold standard of NaOCl-based CMCR agents.

Enzymatic CMCR agents were introduced by Bussadori, who used papain enzyme to formulate a product named Papacarie, a word that means “caries eater” in Portuguese.⁷ Papain enzyme is extracted from the latex of leaves and fruits of the green adult Carica Papaya tree, which is cultivated in tropical regions such as Brazil, India, South Africa, and Hawaii. It is a proteolytic enzyme with bactericidal and anti-inflammatory actions. Bussaduri et al. reported that the enzymatic caries removal method was based on the fact that this proteolytic enzyme causes infected carious tissues to lose the function of the antiprotease α-1-antitrypsin, which further inhibits protein digestion in collagen-based tissues but not in affected and sound dentinal tissue. The aim of the present study was to assess the efficacy of the caries removal ability of a chemomechanical agent (papain gel) and compare it with that of conventional slow-speed rotary carbide burs and mechanical hand excavators.

The objectives of the present study were to assess the caries excavation time and residual caries remaining in terms of depth, length, and area by the enzyme-based (papacarie) CMCR method and compare them with the standard rotary caries excavation method and hand excavator.

MATERIALS AND METHODS

Freshly extracted 30 primary carious molars were randomly collected, as per the inclusion and exclusion criteria, from the exodontia clinic of the Department of Pedodontics and Preventive dentistry under a protocol reviewed and approved by the institutional ethics committee (reference number RADC/PPD/3/17). Freshly extracted human nonrestorable carious primary maxillary and/or mandibular molars with open occlusal cavitation involving dentin were used for the present study. Teeth with existing restorations and hypoplastic teeth were excluded from the present study.

The Occupational Safety and Health Administration guidelines⁸ were followed to disinfect and store the extracted teeth. Any soft tissue and extrinsic deposits attached to extracted teeth were removed using hand scalers, and the teeth were rinsed with normal saline. This was followed by immediate placement and storage of teeth in phosphate-buffered saline (pH 7.2) for not >1 week until use.

Thirty extracted teeth that were used for the present study were selected using a simple random sampling technique and then distributed equally among two major categories (15 each). Selected teeth were sectioned mesiodistally in a longitudinal plane through the center of the carious lesion into two halves, using a diamond-impregnated circular disk under a water coolant at low speed. Those two halves were subdivided further into two groups. Each group consisted of 30 teeth halves. Thus, each category comprised 15 teeth. A total of 30 teeth were used (Table 1). In each group, the corresponding halves were sectioned off randomly but in equal numbers into two categories as follows:

**Table 1:** Mean time taken for caries removal
Values of descriptive statistics	(Group I) (n = 30)	(Group II) (n = 30)	(Group III) (n = 30)	(Group IV) (n = 30)
Mean ± SE	124.63 ± 57.72	90.62 ± 46.20	122.78 ± 51.53	205.98 ± 39.98
Median	112.05	79.73	116.27	207.05
Range	60.33–273.19	51.01–236.72	55.65–203.16	132.98–262.12

Category 1 (15 teeth): Group I hand excavator (n = 15 halves) and group II carbide bur (n = 15 halves).
Category 2 (15 teeth): Group III hand excavator (n = 15 halves) and group IV papain gel (n = 15 halves).

The roots of all the teeth specimens were then embedded in cylindrical molds (approximately 1 cm in diameter) (Fig. 1) with self-cure acrylic resin for ease of handling, and excavation of enamel margins, if deemed necessary, was eliminated with round diamond burs using a high-speed handpiece in order to allow proper access to carious dentin. Caries was excavated from the tooth sections in each group as follows:

Fig. 1: Embedded Specimen

Category 1: Using carbide burs for group I and group II with a hand excavator.
Category 2: Using a hand excavator for group III and papain gel for group IV.

A round carbide bur (RA #6) in a slow-speed handpiece at 1000 rpm (Fig. 2) with a uniform grip was used to excavate caries beginning from the center to the periphery of the carious lesion. The cavity was rinsed with excess water, dried gently, and examined visually with a probe. Excavation of dentin was done till it appeared to be caries-free according to the conventional visual and tactile criteria—dentin coloration, hard dentin on probing, and a sharp scratching sound of the dentin using a dental explorer.

Fig. 2: Digital Stroboscope

Similarly, caries was removed using a hand excavator with a uniform grip in a scooping motion beginning at the periphery and later at the center of carious lesions by the same operator until hard dentin was reached.

Caries excavation by papain gel was done by applying gel over the carious surface for 30 seconds, and when the gel became turbid, excavation was done using the non-sharp end of the excavator. Gel application was repeated till the tooth surface appeared caries-free, and then the tooth was rinsed with normal saline, dried, and checked accordingly by the same operator until hard dentin was reached.

The evaluation criteria using visual and clinical aids for the assessment of caries removal were initially discussed with an independent coinvestigator. Without knowledge of the assignment of teeth to treatment groups, the blind coinvestigator examined each cavity to determine the completeness of the caries excavation. If any carious tissue was detected, the treatment was continued until the area was judged caries-free.

The total time taken (in seconds) from the beginning of caries excavation until final approval of completion was recorded for each tooth section using a stopwatch. The specimens were removed from the jig, and longitudinal serial sections, as many as possible (minimum two in number), in a mesiodistal plane, were obtained.

The sections were thinned on an Arkansas stone (approximately 40–50 µ)and finished using 1200-grit sandpaper. Each section was stained with the Seek (Ultradent)(Fig. 3) caries detecting dye for 10 sec and then rinsed off using saline. The stained sections were mounted on the glass slide using distyrene, plasticizer, and xylene-balsam mounting medium and glass coverslips, and the medium was allowed to dry for 4–5 days (Fig. 4).

Fig. 3: Seek Caries Detection Dye

Fig. 4: Sectioned mounted Specimen

The sections were then observed under the stereomicroscope at 12.5 fold magnification, and the images were captured (Fig. 5).

Fig. 5: Stereomicroscope

The mean depth, mean length, and mean area of the stained dentin for each tooth half were calculated (Fig. 6).

Figs 6A and B: Sections under Stereomicroscope

Statistical Analysis

Collected data were statistically analyzed with the help of Epi Info^TM 3.5.3. A descriptive statistical analysis was performed to calculate the means with corresponding standard error (SE). One-way analysis of variance followed by post hoc Tukey’s test was performed with the help of CD or least significant difference at 5–1% levels of significance to compare the mean values. Statistical significance was set at p < 0.05.

RESULTS

Time

As per CD, the results of the study showed the caries removal mean time for group IV (Papacarie group), when compared to other groups, was significantly higher (p < 0.01). Group II had a significantly lower mean time than that of other groups (p < 0.01) (Tables 1 and ²).

**Table 2:** Mean difference in time taken
Group	Difference of means	p-value
I vs II	34.01	<0.05*
I vs IV	81.35	<0.05*
II vs III	32.16	<0.05*
II vs IV	115.36	<0.01*
III vs IV	83.20	<0.05*

*p < 0.05

Area of Residual Dentin

As per the CD, the mean of group II had a significantly lower mean area of residual caries than other groups (p < 0.01) (Table 3).
A significantly lower mean of residual caries was found in group IV than that in group I and group III (p < 0.05) (Table 4).

**Table 3:** Area of residual dentin
Values of descriptive statistics	(Group I) (n = 30)	(Group II) (n = 30)	(Group III) (n = 30)	(Group IV) (n = 30)
Mean ± SE	2.70 ± 1.17	0.87 ± 0.51	2.52 ± 1.49	1.86 ± 0.98
Median	2.21	0.84	2.33	2.08
Range	1.50–5.12	0.23–1.97	0.28–5.55	0.57–3.50

**Table 4:** Mean difference in residual dentin
Group	Difference of means	p-value
I vs II	1.83	<0.05*
I vs IV	0.84	>0.05 NS (nonsignificant)
II vs III	1.65	<0.05*
II vs IV	0.99	<0.05*
III vs IV	0.66	>0.05 NS

*p < 0.05

DISCUSSION

Fundamentals of dental treatment have definitely changed over a period of time, as today, we have more evidence provided through extensive research to reassess the traditional approaches to caries treatment.⁹

The coronavirus disease of the 2019 pandemic reinforced a well-established philosophy and the use of minimal intervention for the treatment of dental caries (ALOP 2020).¹⁰ To minimize the generation of aerosols, which is done with traditional rotary tooth removal methods to prevent cross infection, CMCR methods, such as papain gel, can reinforce the concept that less is more, in contrast to traditional caries removal methods, which require removing large amounts of hard, sound dental tissue to treat caries (Frankenberger and Meerbeek 2018).¹¹ Current situations have opened up new doors to explore better methods and newer research on minimum intervention methods, such as the CMCR technique like papain gel and its uses, which have not yet been fully explored, to guide future research and treatment.

Carious dentin removal, which is infected without affecting the dentin, and can be remineralized, has been the mainstay of conservative restorative dentistry. But a quick, simultaneously controlled method of selective carious dentin removal has remained elusive. A rotary instrument capable of being used at low speed with its cutting ability limited to the infected layer and initial layer of affected dentin has a conceptual appeal.¹ Hence, current in vitro research was undertaken to assess the efficacy of papain gel for the removal of carious dentin in comparison to the commonly used hand excavation and carbide burs in extracted human primary molars.

The conventional visual and tactile criteria were used to assess caries removal because they are the most widely used clinical criteria¹² and a standard prerequisite for future treatment success.¹³ However, these criteria are still subjective and are influenced by the examiners’ experience. Therefore, a histological examination was considered necessary to obtain reproducible results.¹⁴ Mean caries left in the study were assessed/calculated/estimated in terms of length, depth, and area for carbide burs, hand excavators, and papain gel.

The mean results showed that the carbide bur left the least amount of residual stained dentin and was the most effective method of caries removal, followed by papain gel and the hand excavator. Hand excavator left the maximum amount of residual stained dentin and was found to be the less efficient method within the limitations of this study. The results were similar to a previous study by El-Tekeya et al.¹⁵

The negative rake angle of conventional carbide burs increases their efficiency in cutting hard tooth tissues. Excessive dentin removal generally happens with carbide burs due to limited tactile sensitivity can lead to less-controlled movement of the instrument. Hand excavation and removal by papain gel provide tactile feedback and controlled movements while scooping out dentinal caries. Hence, it can be considered self-limiting and less damaging to dental tissues.¹⁶

The hand excavator left a greater amount of residual-stained dentin, possibly because it removes softened tissue with more sensitive tactile feedback than papain gel and carbide bur, so this method is the most self-limiting of the three.

The mean time taken for caries removal by carbide burs, hand excavator, and papain gel were 90.62 ± 46.20, 124.63 ± 57.72, and 205.98 ± 39.98 seconds, respectively, which shows papain gel group was the most time-consuming method followed by the hand excavator. Excavation with a carbide bur proved to be the most time efficient.

It is a well-established fact that hand excavation consumes more time in comparison to rotary techniques for caries removal. The papain gel method of carious dentin removal took more time than carbide burs to remove dentinal caries. These results are in accordance with those obtained in studies by Ericson et al.¹⁷ and Nadanovsky et al.¹⁸ The application time and working time of papain gel and the need to put more gel during caries excavation were probably reasons for more time for caries excavation.

The duration of treatment is often a challenge in treating pediatric dental; this can be a potential limitation. However, in a clinical situation, the difference in time consumption between papain gel, hand excavator, and carbide bur may be less because papain gel and a hand excavator usually do not require local anesthesia, thus reducing the actual operative period.¹⁹

Drawbacks of Study

Several studies show that after partial caries excavation if the cavity is appropriately sealed with a cariostatic restorative material having good marginal adaptability, carious lesions can be arrested for as long as 10 years. Further longitudinal studies for a longer duration are recommended to evaluate the risk of residual carious dentin after caries excavation by Papacarie on the prognosis of the tooth.

Caries-detector dye in differentiating the number of dentinal caries to be excavated from the one to be left is debatable. Few studies are of the opinion that caries-detecting dyes are not specific since they do not stain bacteria and often stain the normally less mineralized dentin at the pulpal periphery and the enamel-dentin junction. A more objective method like laser autofluorescence for the detection of carious dentin could yield more accurate results.

This study can be further supported by microbiological validation to find the proportion of bacteria in the residual carious dentin after excavation and their significance.

CONCLUSION

The use of papain gel can be considered a minimally invasive method for the removal of caries, having almost the same efficacy and effectiveness as the commonly used caries removal methods with the advantage of being gentler on dentinal tissue without aerosol generations.

ORCID

Paras Angrish https://orcid.org/0000-0003-0721-0353

Ashish Kamboj https://orcid.org/0000-0002-1836-6786

Dempsy MM Chengappa https://orcid.org/0000-0002-5014-7030

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