Comparative Study Between Smart Bur II and Traditional Carbide Bur in Selective Removal of Caries in Permanent Molars
Condition: Dental Caries in Children
MeSH terms: Dental Caries
Study type: Interventional

Summary: 
      A more biological and conservative technique of caries removal has emerged with minimally
      invasive restorative dentistry's advent. As a result, Smart Burs II has become a
      self-limiting, sensitive tool for removing caries. The current study aimed to validate and
      contrast the polymer burs' efficacy (Smart Burs II) versus conventional burs (Carbide burs)
      for infected carious dentin's selective removal in permanent first molars. Thirty permanent
      first molars fulfilling the inclusion criteria were chosen in 8-11 years old children with
      class I occlusal carious lesions. Group 1 (n=15) and Group 2 (n=15) were randomly assigned to
      have carious dentin removed utilizing standard carbide bur and a smart Bur II, consecutively.
      By employing caries detector dye, the effectiveness of caries removal was quantified as 0, 1,
      2, 3, 4, or 5. The volume of removed carious tissue was recorded using impression material
      which was inserted into a calibrated insulin syringe. A statistically significant difference
      was discovered in the volume of removed carious tissue between both groups, while the
      efficiency of caries removal using either bur has no significant difference. Smart Bur II was
      more conservative in the carious dentin's removal than carbide bur. Smart Bur II was as
      efficient as carbide bur in caries removal.
    

Detailed description: 
      One of the prime goals of the evolution of minimally invasive dentistry is conserving healthy
      tooth structure by eliminating infected carious dentin while retaining impacted carious
      dentin intact and minimizing the needless destruction of teeth. Dentin carious lesions is
      formed of two distinct layers that differ from one another regarding their microscopic
      structure and physiological and bacteriological characteristics. The external superficial
      infected layer is soft, heavily contaminated by bacterial invasion, and incapable of being
      repaired owing to the collagen fibers' irreversible denaturation. While the affected dentin,
      which is a hard substance with few bacteria and can be remineralized due to limited collagen
      degradation, is located beneath the infected layer.

      Conventional caries removal could possibly be traumatic as it tends to remove both infected
      and affected dentin, which may induce an unneeded weakening of the tooth structure and often
      leads to overextended cavities. Moreover, it has deleterious thermal influences on the pulp.
      Accordingly, the dental industry has recently witnessed the emergence of the polymer bur,
      which manufacturers claim is the best for selectively removing caries while minimizing the
      patient's discomfort. By introducing a polymer prototype bur in 2003, a potential substitute
      for traditional techniques of removing carious dentin has emerged. This self-limiting polymer
      bur is known as SmartBurTM, a variant of SmartPrepTM (SS White, Lakewood, NJ, USA). It is a
      single-use bur-like instrument constructed of a polymer with a lower hardness than healthy
      dentin. Different sizes are available; #4, #6, and #8 for right angle latch handpieces.

      Polymer bur tools resemble conventional burs in appearance, but they are made of unique
      polymer material rather than metal. The cutting edges are not spiral, like those of a shovel.
      The polymer material was designed to be softer than healthy dentin (Knoop hardness 70-90) but
      harder than carious, softening dentin (Knoop hardness 50-70) (Knoop hardness 0-30).
      Therefore, it has a knoop hardness of 50 kg/mm2, and its cutting elements effectively remove
      soft dentin but cannot remove healthy dentin.

      Materials and methods Sample size calculation The minimum required sample size will be 15
      molars in each group. Thus, a total of thirty permanent first molars will be divided into two
      groups for this study. The sample size was computed as per G*Power software version 3.1.9.3.

      Allocation of samples A 1:1 allocation ratio was used to allocate each of the 30 selected
      permanent first molars to either Group 1 (Carbide Bur group) or Group 2 (Smart Bur II group).

      Clinical Procedures and Grouping At the beginning of the dental visit, the "tell-show-do"
      method was performed, in which the child was introduced to all instruments and equipment used
      in the treatment session14. A periapical radiograph was taken for each carious molar. The
      proper isolation was conducted for the selected molars using a rubber dam and suction. local
      anesthesia was administered during the trial for each patient. The volume of the unprepared
      carious cavity, for both groups, was measured using impression material (Zhermack Oranwash L
      light c-silicone), which was inserted in a calibrated insulin syringe and consequently
      injected into the cavity before caries removal.

      After recording the cavity's volume , the impression material was washed with water. The
      outline form of the cavity of all selected molars was established using a high-speed
      handpiece and round carbide bur. The removal of carious lesions was carried out for all the
      selected carious teeth, and they were split into two groups, as per the types of burs used
      for the removal of caries:

      Carbide bur group (Group 1):

      Using a slow-speed handpiece and round carbide burs in sizes #12, #14, and #16, based on the
      lesion's size, caries was removed. When hard dentin was found using a dental probe, carious
      dentin removal was stopped.

      Smart Bur II group (Group 2):

      As per the manufacturer's recommendations, carious tissue was removed utilizing smart polymer
      burs of sizes #4, #6, and #8, depending on the cavity's size, running at a slow speed without
      water coolant, in circular motions from the center of the lesion outward. Carious dentin
      removal ceased when the instrument became macroscopically abraded and sharpened and could no
      longer remove tooth tissues.

      Caries detector dye (Red Detector, Cerkamed, Medical Company, Poland) was applied to all
      treated teeth of both groups as one drop on the defective area and waited 5-10 seconds. After
      that, irrigation with water for ten seconds was applied as recommended by the manufacturer's
      instructions. After drying the cavity, the examination was executed using the dental mirror
      to detect stained dentin sites. Points intensively dyed in red indicated residual caries.
      Then, the stained dentin was selectively removed by carbide and polymer burs according to
      each group. This process was frequent until no stain persisted in the cavity. After the full
      removal of caries in both groups, the cavity volume was again recorded using the same
      previous procedures of cavity volume measurements.

      Assessment procedures Tactile and visual criteria were utilized to validate the clinical
      efficacy of caries removal in both groups. Moreover, caries removal was confirmed by
      utilizing caries detector dye (red detector, Cerkamed). Points intensively dyed in red
      indicated carious dentin. Efficacy was rated and given a numerical value as 0, 1, 2, 3, 4,
      and 5 according to the Ericson rating scale, as shown in (Table 1).

      Table 1 Definition of the scores for caries removal Score Definition 0 Complete removal of
      caries

        1. Caries is found at the cavity floor.

        2. Caries is found at the floor and/or one wall.

        3. Caries is found at the floor and/ or two walls.

        4. Caries is found at the floor and /or more than two walls

        5. Caries is found at the margins, walls, and floor of the cavity.

      Using impression material and a calibrated insulin syringe for both groups, the amount of
      removed carious tissue was measured by computing the difference between the cavity's initial
      volume before caries removal and the final volume of the cavity after caries removal (as
      previously explained).

      All treated cavities were finally restored once all caries had been eliminated.
    

Intervention name(s): caries removal by carbide bur; caries removal by polymer bur II
Intervention type(s): Device; Device
Intervention description(s): caries was removed using a slow-speed handpiece and round carbide burs in sizes #12, #14, and #16, based on the lesion's size. When hard dentin was found using a dental probe, carious dentin removal was stopped.; carious tissue was removed utilizing smart polymer burs of sizes #4, #6, and #8, depending on the cavity's size, running at a slow speed without water coolant, in circular motions from the center of the lesion outward. Carious dentin removal ceased when the instrument became macroscopically abraded and sharpened and could no longer remove tooth tissues.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment