Assessing Caries Removal Efficacy and Pain Perception in Children, Using Smart Bur Versus Carbide Bur: A Randomized Clinical Study

Introduction

Dental hard tissues can frequently be affected by a persistent condition known as dental caries, which has significant effects on human health [1]. The oral and systemic complications exacerbated by caries diminish quality of life and lead to a considerable financial burden for the affected individual [1]. Dental caries is considered as a multifactorial disease resulting from the interaction of diet, microbial load, host factors, and time [2]. The global prevalence of dental caries in primary teeth was reported to be 46.2% [3], whereas in Saudi Arabia, the prevalence ranged from 72% to 84% among children, as reported in a recent systematic review, indicating a major cause for concern [4]. No matter the age, caries has a negative influence on all demographic groups [2].

Caries management encompasses the administration of targeted interventions to halt the progression of existing dental caries and address active lesions that are non-self-cleansing, with the objective of managing caries development at the individual tooth level [1,5]. Nonselective caries removal involves removal of soft and firm dentin, irrespective of the proximity of the carious lesion to the pulp [5], whereas selective caries removal involves selectively removing caries, considering the closeness to pulp, and therefore, sound dentin is left preserved [5]. The former method is deemed nonconservative and excessive, with higher rates of pulp exposure, when compared with the latter [4].

Over the years, the development of optimal tools and techniques for the efficient and prompt management of carious lesions has led to the use of hand instruments, metal carbide burs, diamond burs, chemo-mechanical preparations, air abrasion, and sono-abrasion [6]. Conventional methods include the use of hand instruments, metal carbide burs, and diamond burs, whereas the use of chemo-mechanical preparations, air abrasion, and sono-abrasion are considered modern techniques [6]. Attempts for the preservation of sound dentin and a conservative preparation is gaining more priority in contemporary clinical practice [7]. Mechanical caries excavation techniques using carbide burs and diamond burs can remove non-decalcified enamel as well as dentin, but it cannot differentiate between carious and sound dentin during cavity preparation [7]. Although chemo-mechanical caries removal techniques do not affect the sound dentin, they are reported to be quite time consuming [8]. Studies have also reported the inability of air abrasion to remove soft carious lesions and the inadequate preparation of cavities by sono-abrasion techniques [9,10]. The drawbacks of these methods have led to the discovery of an alternative method. A polymer prototype bur with a slightly lower mechanical property than that of sound dentin was developed by Boston et al [11].

Compared with the conventional burs, which are made from metal, polymer burs have a cutting element made of softer polyamide polymer material [12]. This helps in minimal cutting of the dentinal tubules, leading to a minimally invasive caries excavation [12]. The polymer bur has shovel-like cutting edges instead of spiral ones, like traditional burs [12]. It has a Knoop hardness of 50, making it harder than carious dentin (0–30 Knoop hardness) but softer than sound dentin (70–90 Knoop hardness). The polymer cutting edge wears off when it comes in contact with harder structures, like sound tooth, and could become blunt [12]. Thus, the infected dentin is removed, whereas affected dentin is preserved [12]. Commercially available forms of polymer burs, such as SmartPrep SS White burs (Lakewood, NJ, USA), have polyether-ketone-ketone polymer [13].

Generally, dental procedures are thought to cause discomfort, and this belief is especially strong in children [14]. Dental fear indeed heightens the perception of pain in children. The triggers of dental fear include noises, vibrations, administration of local anesthesia, and the use of high-speed handpieces [14]. Traditional mechanical cavity preparation frequently causes discomfort due to its non-conservative approach [14]. Hence, quicker measures using less pain stimulation has to be included while treating them [12]. Although there are studies [13,15–17] reporting the caries removal efficiency and time consumption by polymer burs, there are insufficient data reflecting the behavioral aspects of children while using these burs. Hence, the present study aimed to compare outcomes from dental restoration for caries using smart burs and carbide burs in primary molars among 40 children aged between 6 and 12 years. This study also assessed factors including time taken for caries removal, efficiency of caries removal, intensity of pain, and patient satisfaction to determine the clinical success of each method.

Material and Methods

RESEARCH DESIGN, ETHICAL APPROVAL, AND INFORMED CONSENT:

This single-blinded randomized clinical study received approval from the Standing Committee for Sabbatical Leaves, Publication and Research Ethics, Jazan University (HAPO-10-Z-001) with reference number (REC-45/10/1069), dated April 28, 2024. The detailed study protocol, encompassing minute details, was elucidated to the participants’ parents or guardians, and enrollment proceeded upon acquisition of a signed informed consent form. Consent was obtained before the start of the study. The study protocol followed the ethical principles of the Declaration of Helsinki (1964) and its subsequent revisions rigorously.

SAMPLE SIZE ESTIMATION:

Sample size was estimated based on the given formula, with 1 and 0.65 being the proportion of caries lesions completely removed using carbide burs and smart burs, respectively, and a clinically significant difference of 0.35 derived from the earlier study [7].

Where,

By substituting these values, the sample size was estimated to be 15 teeth in each group. The final sample size used in the study was 20 teeth in each group.

INCLUSION CRITERIA: The study initially included 40 children aged 6 to 12 years (average age of 8.5±1.05 years) who visited the Pediatric Dental Department’s outpatient section. The criteria for inclusion required that the children were in good physical and mental health, with no significant medical history. Additionally, they needed to exhibit positive or definitely positive behavior as determined by Wright’s modification of the Frankl behavior rating scale (FBRS) [18,19] during the initial assessment. Another key inclusion criterion was the presence of a minimum of 2 asymptomatic carious lesions in primary molars, with visible dentin involvement in primary molars fulfilling International Caries Detection and Assessment System code 4 [20], and, using radiographs, fulfilling International Caries Classification and Management System RB4 (radiolucency reaching the middle one-third of dentin) [20]. Lastly, the study participants’ parents provided written consent and expressed willingness to take part in the study.

EXCLUSION CRITERIA: Children under 7 years old, those exhibiting symptoms of irreversible pulpitis and dentoalveolar abscess, children who showed negative or definitely negative behavior based on Wright’s modification of FBRS [18,19] at the first examination, and children with medical or mental health issues were not included in the study.

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Thirty children requiring restorative treatment were randomly assigned to 1 of 2 groups using a simple randomization method with a 1: 1 allocation ratio. The allocation concealment was achieved through the SNOSE (sequentially numbered, opaque, sealed envelopes) method. Envelopes of matching size and color were placed in a box labelled A and B. Participants selected an envelope and revealed the corresponding label. Group 1, the carbide bur group (Figure 2), consisted of 20 children who underwent dental caries removal using a carbide conventional rotary bur. Group 2, the smart bur group (Figure 3), consisted of 20 children who received dental caries removal with Smart burs.

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A single operator performed the entire restoration process for all participants in the study, to minimize any operator-related bias. Treatment-specific equipment and procedures were introduced and demonstrated to the participants using the “tell-show-do” approach. None of the patients in either group received anesthesia. The tooth in question was isolated. Caries-detecting dye (Figure 5) was applied using an applicator tip and then rinsed with water. The affected area was treated with a high-speed handpiece with carbide bur to excavate the caries. The removal of caries was confirmed using a caries detector. Following caries removal, the caries detector was applied for 1 min to the remaining lesion. The area was then rinsed with water, and the effectiveness was assessed using the Ericson scale [21], as follows: 0, caries removed completely; 1, caries present in the base of the cavity; 2, caries present in base and/or wall; 3, caries present in base and/or 2 walls; 4, caries present in base and/or more than 2 walls; and 5, caries present in base, walls, and margins of the cavity. Any remaining caries if present were removed, and permanent restoration with glass ionomer cement was completed.

When compared with the carbide bur group, the smart bur group burs showed wearing off the cutting edges when the bur came in contact with affected dentin (Figure 6A, 6B).

OUTCOMES:

The time taken in each method was measured and documented from the beginning of caries removal until the cavity was confirmed to be caries-free, using a stopwatch. Pain levels were assessed using the Face Leg Activity Cry Consolability (FLACC) [22] and Wong-Baker FACES pain rating scale (WBS) [23], and behavior of the child through the Frankl behavior rating scale (FBRS) [18,19].

FACE LEG ACTIVITY CRY CONSOLABILITY SCALE: The FLACC scale [22] was used, as it a reliable method for objective pain assessment. The FLACC focuses on 5 different behavioral domains to determine pain severity. Facial expressions, including grimacing and frowning, are observed to determine the presence of pain. Leg movements or tightness are examined to detect signs of agitation or stress. This part involves assessing an individual’s overall physical mobility, which includes monitoring for indicators of restlessness or reluctance to remain still. Vocal expressions of distress, such as crying or vocalizations, are also considered. Consolability assesses an individual’s ability to provide comfort or solace. Each domain receives a score ranging from 0 to 2, with 0 indicating no pain and 2 the most severe pain. The total FLACC score is the sum of individual domain scores, ranging from 0 to 10. A higher score indicates more severe pain.

WONG-BAKER FACES PAIN RATING SCALE: The WBS [23] is a tool for assessing subjective pain, which features a range of 6 facial expressions. This scale consists of 6 distinct face expressions. Each expression corresponds to a numerical value from 0 to 10, indicating the intensity of pain. Pain levels are categorized based on the scores: 0 to 4 indicates mild pain, 4 to 6 indicates moderate pain, and 8 to 10 indicates severe pain. The scores were used to classify the pain levels. Both groups of children were instructed to assess their pain levels using WBS at 3 specific instances: during excavation of caries, during restoration, and at the end of the treatment.

FRANKL BEHAVIOR RATING SCALE: Wright’s adaptation of the FBRS [18,19] was used to evaluate a child’s behavior at different phases throughout the dental treatment. The FBRS scale is esteemed for its methodical evaluation of a child’s cooperation and response throughout dental procedures. The children’s behavior was evaluated during several stages of the dental treatment, including intraoral examination, radiographic imaging, excavation of caries, during restoration of tooth, and after the restoration of tooth.

STATISTICAL ANALYSIS:

Statistical analysis was done using a standard statistical software (SPSS 20, IBM Corp, Armonk, NY, USA). Data normality was checked with the Shapiro-Wilk test. Group allocation based on age and sex was examined using the chi-square test. Intergroup comparisons of time taken for caries removal was conducted using unpaired t test, and comparison of caries removal efficiency, patient behavior, intensity of pain between the 2 groups were conducted using the Mann-Whitney U test.

Results

TIME CONSUMPTION FOR EXCAVATION:

A very high statistically significant difference (P<0.001) was noted for the time needed for excavation of caries, with smart burs taking a longer time (5.2±1.16 min) than carbide burs (2.74±0.91 min), as shown in Table 2.

EFFICENCY OF CARIES REMOVAL:

On analyzing the ordinal parameters, a significant difference was observed for the Ericson scale, with the lowest scores being reported in the carbide bur group [0(0, 0.25)], as shown in Table 3.

PAIN PERCEPTION DURING PROCEDURE:

During excavation of caries and restoration, most of the participants in the carbide bur group [6(6, 8), 2(2, 2.5)] had higher WBS scores than did the smart bur group [2(2, 4), 0(0, 0.5), and the differences were highly significant (P<0.001). Evaluation of FLACC scores during local anesthesia delivery revealed a very high level of statistical significance (P<0.001) between the 2 groups, with a higher median score recorded in the carbide bur [4.5(2, 5.25)] group, as shown in Table 3.

PATIENT BEHAVIOR DURING PROCEDURE:

A statistically significant difference was observed for FBRS scores before excavation in the smart bur group, with a highest median of “4” reported in the mandibular arch, whereas a statistically significant difference in Ericson scores was observed in the carbide group, with a higher score seen in relation to the maxillary arch, as shown in Tables 4 and 5.

Discussion

LIMITATIONS:

One potential limitation of this study was its narrow scope in comparing smart burs with only carbide burs, whereas incorporating other minimally invasive methods could have provided a more comprehensive analysis. Additionally, the study focused on a specific age group of children. We suggest that future research should explore the acceptability of smart burs among a wider pediatric population. Owing to the benefits and drawbacks identified in our study, we concluded that smart burs can be a promising tool for restorations in children. It serves as an exceptional instrument for dentinal caries removal, with its unique ability of removing infected dentin while preserving the deeper affected dentin. This approach minimizes pain and enhances cooperation among pediatric patients.

Conclusions

Pain perception among children was lower and overall satisfaction was higher in the smart bur group, whereas caries removal efficiency was higher in the conventional carbide bur group. Therefore, we conclude that restoration using smart burs minimizes pain and enhances cooperation of pediatric patients.