Comparative study of caries removal using BRIX 3000 and classic mechanical method

SUMMARY Introduction In dental practice, despite the constant improvement of dental equipment and materials, caries removal using rotational instruments is still not a satisfactory way. The caries removal treatment constantly offers numerous alternatives in order to replace machine tools, and one of them is the chemo-mechanical method. The aim of this paper is to examine the effectiveness of the chemo-mechanical method of caries removal using BRIX 3000 and classic method. Material and Method We used BRIX 3000; a material intended for atraumatic caries removal. Both caries elimination methods were performed in 40 patients with evident carious lesions. Twenty patients underwent atraumatic caries removal while in the other twenty carious tissue was removed using rotating instruments. Results BRIX 3000 was effective in caries removal. A significant reduction in the use of local anesthetics was noticed. Patients did not experience discomfort or pain during treatment with BRIX 3000, but the duration of caries removal using this atraumatic method was significantly longer than with the classic method. Conclusion Atraumatic method of caries removal is an adequate alternative to conventional therapeutic procedures for caries removal, which finds a place in the domain of modern minimally invasive dentistry.


INTRODUCTION
Dental caries is bacterial disease that leads to progressive demineralization of the inorganic part of the tooth followed by enzymatic disintegration of organic component. For years, the most common way to remove caries and prepare teeth for fillings has been the use of handpieces and burs. The invasiveness of this preparative method is the cause of many side effects such as thermal damage to the pulp, excessive removal of healthy dentin as well as patient discomfort.
Enamel prisms may break during the use of burs and handpieces, not only along the edges of the cavities, but also deeper in the enamel. These cracks can potentially harbor bacteria, causing further penetration into the dentin and growth of caries lesion. When carious tooth structure is removed using burs, some of the healthy part is also removed which weakens the cavity walls and increases the possibility of tooth fracture. With the use of modern materials and adhesive systems, the need for large retention cavities has been eliminated [1].
Taking into account the negative consequences that can occur using rotary preparation techniques, and in order to preserve and protect healthy tissues, in the recent years there has been a huge development of minimally invasive methods of caries removal -air abrasion, lasers, sono-abrasion, chemo mechanical methods (CMCR) etc. [2,3]. CMRC involves the use of gels that selectively remove softened and infected dentin which further facili-tates manual excavation of caries dentin. That way painful and unpleasant sensations are reduced to minimum while there is high efficiency and the treatment is comfortable for patients [4].
BRIX 3000 is a gel containing papain (3,000 U / mg in a concentration of 10%) which was produced in 2012 by Brix Medical Science in Argentina. The unique features of this product are due to the high concentration of papain, which is bio-encapsulated using the exclusive EBE technology (Encapssulating Buffer Emulsion). It provides an ideal pH for the gel, that immobilizes enzymes and releases them during collagen proteolysis. The mechanism of action is exclusively on the necrotic dental tissue by dissolving partially degraded collagen fibers, while healthy dentin, solid and stable structure is not disturbed, as collagen fibers are not demineralized nor exposed.
Numerous scientific papers present data on the effectiveness of chemo-mechanical method of caries removal using BRIX 3000, pointing to it as an alternative to rotary handpieces. The results show complete removal of caries and clean cavity after several gel applications. These studies also include answers about patients' acceptability. Most of the respondents accepted the treatment well and they perceived it as more pleasant and less painful than the classic method of caries removal [5]. However, there are small number of studies that evaluate the effectiveness of CMRC in the adult population.
Therefore, in an attempt to bridge this gap, our study was conducted to evaluate the effectiveness of caries re-moval methods, in order to find the best option that will be routinely used in clinical practice. The main goal was to find method that will be successful in caries lesions removal without damaging the surrounding tooth structure, distinguishing infected dentin from healthy, reducing healthy structure removal, preserving it and stimulating the remineralization process.
The aim of this study was to compare the efficacy of two caries removal techniques, atraumatic caries removal using BRIX 3000 and classic method using rotary handpieces. Treatment duration, effectiveness in caries removal, presence/absence of pain during treatment, and patient's perception of treatment were evaluated.

MATERIAL AND METHOD
The study used the material BRIX 3000 for chemo-mechanical removal of caries with papain as its main ingredient (30,000 U/mg 10%). Papain is an endoprotein, similar to pepsin present in gastric fluid, which has bactericidal, bacteriostatic and anti-inflammatory action. 100 ml of BRIX3000 gel contains the following components: Papain 30,000 U / mg 10 g, Propylene Glycol, Citric Pectin, Triethanolamine, Sorbitan Monolaurate, Disodium Phosphate, Monopotasic Phosphate, Toluidine Blue, distilled water q.s. 100 ml.
The clinical part of the examination took place at the Clinic for Restorative Dentistry and Endodontics at the Faculty of Dentistry in Skopje. The study group consisted of patients aged 18 to 70 years of both genders, who after the examination were found to meet the criteria for the inclusion in the study: -At least one carious lesion was found in each patient. -The treated teeth were vital. -Patients had previous experience at the dentist, where they were treated with similar carious lesions using a conventional method. -The respondents in the personal history did not have data on possible allergy or hypersensitivity to drugs or other medical devices.
This study included 40 patients who were divided into two groups -experimental (20 carious teeth), where caries lesions were removed with BRIX3000 and control group (20 carious teeth), where the classic method of caries removal with handpieces and burs was used. The beginning of the preparation in both groups of respondents was conducted by using a high-speed handpiece, in order to start the preparation of the cavity.

Chemo-Mechanical Method of Caries Removal
Chemo-mechanical method of caries removal was performed by applying the BRIX 3000 gel in the cavity, where the gel was applied for about 30 seconds in order to soften the carious dentin. Then, it was removed by hand instruments -excavators (Figure 2),   without excesive pressure, by applying rotational movements and scratching the softened dentin. The remnants of the gel and carious tissue were removed using air. The procedure was repeated until the altered dentin was completely removed. Drying the cavity was followed by inspection, using explorer and evaluation of caries removal was done by applying the caries detector.

Conventional Method of Caries Removal
In the control group, the carious tissue was removed by machine rotating instruments and carbide borers of different shapes and sizes. The efficacy of caries removal in this group was assessed based on inspection, using explorer and application of caries detector. In the final phase, cleaned cavities were filled with glass ionomer cements, composites or amalgam, depending on the therapist's assessment. The time required for caries removal using both methods was measured and recorded for each patient individually. The efficiency of caries removal after the application of both methods was determined under artificial lighting, by inspection, using explorer and then appropriately recorded in the questionnaire. After the completion, the patients were asked questions related to previous experiences at the dentist, perception of the treatment and comparison with the conventional method, as well as the presence and intensity of pain during caries removal. All data were recorded and separately analyzed in a previously prepared questionnaire.

RESULTS
There was no significant difference between respondents from both groups (p> 0.05) in terms of regularity of visits to the dentist (once in 12 months). However, 8 patients (40%) treated with the BRIX 3000 system, and 4 (20%) treated conventionally go to dentist once a year, while the majority of the respondents from both groups (60% of the experimental and 80% of the control group) still have no habit of annual visit to the dentist (Table 1 and Chart 1). Subjective perception of treatment was determined as painless treatment, mild pain and severe pain. In the experimental group, 14 respondents (70%) considered the treatment painless, 4 (20%) of them had mild pain during the treatment, and only 2 (10%) described the pain as severe. On the other hand, in the control group, only 3 respondents (15%) experienced the treatment as painless, 9 (45%) had mild pain, and 8 (40%) had severe pain. This difference between the two analyzed groups was highly statistically significant (p <0.001). The patients treated with the chemo-mechanical method were significantly more likely to consider caries removal as a painless treatment than the patients treated using conventional method ( Table 2 and Chart 2).  Yates corrected Chi-square = 0.71 p = 0.4 Table 3 and Chart 3 present the average durations of the preparations for the individual classes of cavities from the experimental group, as well as the shortest and the longest duration of the preparation of the cavities. Class III cavities had the lowest average preparation time of 8.0 ± 4.2 minutes, while the longest time of 12.8 ± 2.8 minutes was needed for Class II cavities. The duration of the preparation of the 5 classes of cavities from the control group are presented in Table 4 and Chart 4. The average duration time of preparation was the shortest for Class III of 3.3 ± 1.5 minutes and Class V of 3.6 ± 1.1 minutes, while on average the preparation time for Class II was 9.9. ± 2.5 minutes. The evaluation of the effectiveness of the treatment in the study was analyzed through complete or partial caries removal. Complete caries removal was achieved in 17 (85%) patients treated with the BRIX 3000 system, and in all 20 patients treated with the conventional method. This difference in the distribution of patients with completely and partially cleaned carious lesions, depending on the type of method applied was statistically not significant (p > 0.05) ( Table 5 and Chart 5).

DISCUSSION
The development of systems for chemo-mechanical caries removal has come from the desire of patients for painless caries removal, without the use of drills and less unpleasant sensations [6]. These are perhaps the most common reasons for postponing dental visits, as well as regular check-ups. The data we have received from the patients regarding their consistency of visiting dentist, indicate that most of them (60% of the experimental and 80% of the control group) do not have the habit of regular annual check-ups, and the most common reasons for visiting dentist are sensitivity or painful sensations in the area of the teeth or gums (Table 1 and Chart 1). The knowledge that this is a new and painless method that avoids the use of drills and local anesthesia, had a favorable effect on most patients and 80% of respondents expressed satisfaction with the treatment used. Patients who preferred conventional method often said the reason was the length of treatment. Most clinical studies report similar results [7][8][9][10]. The possibility of painless caries removal without prior application of local anesthesia is a great advantage of the chemo-mechanical method. This is due to the selective action of the Brix gel on carious dentin, the absence of thermal stimulation, pressure and vibrations that develop during rotary preparation. Removing caries lesions using hand instruments -excavators, additionally contributes to painless treatment, because their blades remove only carious tissue without damaging healthy dentin [11]. All patients in the experimental group had previous experience with mechanical caries removal, which enabled them to compare directly the two techniques. The knowledge that this is a new and painless method, without using drills and local anesthesia, had a favorable effect on most of them and 70% of respondents expressed satisfaction with applied treatment. Patients who preferred conventional method often indicated the length of treatment as the reason (Table  2 and Chart 2) as found similarly in other studies [8,12,13].
A review of the literature indicates an interesting fact about the patient's perception of the duration of treatment: a significant percentage of respondents had the impression that the removal of caries by the chemo-mechanical method lasts shorter or perhaps the same as the removal of caries with the classical method. This is probably due to less uncomfortable feeling during chemo-mechanical method due to the absence of sounds, vibrations and pain making patients more relaxed [14]. The average duration of the preparations of the individual classes of cavities within the experimental group ranged from 8 minutes for the class III cavities to 13 minutes for the class II cavities (Table 3 and Chart 3). In the control group, the duration of the preparation of the 5 classes of cavities was much shorter and ranged from 3.3 min for class III cavities to 9.93 min for class II cavities (Table 4 and Chart 4). There was a significant difference in duration of chemo-mechanical caries removal between class I and V cavities which can be explained by the fact that class V cavities are more accessible which is in accordance with the study of Alkhouli et al. [8]. Comparing duration of cavity preparation of all classes between the two groups, we found that for the class I, II and V cavities, caries removal time with BRIX was significantly longer than the same time in the control group (Table 4, 5

and Chart 4, 5).
The effectiveness of caries removal was done on the basis of standard clinical parameters -inspection under artificial lighting, using explorer and application of caries detector. In 85% of cases where chemo-mechanical method was used, complete removal of the caries lesions was achieved, while in the remaining 15% the carious lesion was partially removed. Yazici et al. found residual caries lesions in the area of the enamel-dentinal border after the use of chemo-mechanical removal in 43% [15] while Goldberg et al. found it in up to 60% of samples [16]. After chemo-mechanical removal of the caries, the surface of the dentin was blurred and without gloss, which can cause difficulties in assessing the caries status of the cavity. Caries detector has been very helpful tool for detecting sound dentin.
In clinical practice, carious lesions are often not accessible, so along with the chemo-mechanical method it is necessary to use rotating machine instruments. It has also been observed that for the treatment of initial carious lesions, the chemo-mechanical removal is not the most suitable method, which is in line with the conclusions of Chaussain-Miller et al. [17]. On the other hand, due to the selective action of carious dentin, this method reduces the risk of iatrogenic pulp opening and pushing caries dentin in deep cavities.

The chemo-mechanical method of caries removal
with BRIX3000 is an effective method in clinical conditions. In some cases, it is necessary to use machine rotating instruments to provide access to the carious lesion and give a definite shape to the cavity. Therefore, it is very important to set the correct indication for its use. 2. Chemo-mechanical treatment is usually painless, so the need for application of local anesthetics is significantly reduced. This is why it can be considered as a method of choice in anxious patients, medically handicapped patients, where local anesthesia is contraindicated, as well as in pediatric dentistry. 3. From a clinical point of view, prolonged duration of treatment is considered as a relative disadvantage of the chemo-mechanical method. But, if compared to the classical method where local anesthetics are used for pain, the overall duration of the treatment will not be very different.