|Year : 2020 | Volume
| Issue : 4 | Page : 400-406
Clinical, microbiological, and radiographic evaluation of sealed carious dentin after minimal intervention in primary molars
Meenu Mittal1, Nupur Gupta2, Ashok Kumar3, Radhika Chopra1, Madhumita Barua4
1 Department of Pediatric Dentistry, ESIC Dental College, Rohini, New Delhi, India
2 Department of Microbiology, Jamia Milia Dental College, New Delhi, India
3 Department of Pediatric Dentistry, ITS Dental College and Research, Muradnagar, Uttar Pradesh, India
4 Department of Microbiology, ESIC Dental College, Rohini, New Delhi, India
|Date of Submission||20-Jul-2020|
|Date of Acceptance||06-Dec-2020|
|Date of Web Publication||5-Jan-2021|
Dr. Meenu Mittal
A-29 Ground Floor, Hauz Khas, New Delhi
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: In continuation with the ultraconservative minimal intervention approach for carious lesions treatment, lesion sterilization and tissue repair (LSTR) is a novel concept of using antibacterial drugs to disinfect dentinal, pulpal, and periapical lesions. Aims: The purpose of this study is to evaluate the clinical, radiographic, and microbiologic success rate of indirect pulp treatment (IPT) using a new technique minimal excavation and LSTR with triple antibiotic paste (TAP), for primary molars. Settings and Design: This was randomized controlled trial design. Materials and Methods: Forty-two healthy cooperative children aged 5–10 years having deep carious lesion in primary molars were randomly assigned to receive either traditional IPT with calcium hydroxide or minimal excavation and LSTR with TAP. Follow-up was done at 6 weeks, 3, 6, and 15–18 months intervals, and treatment success or failure was determined by a combination of clinical, microbiological, and radiographic findings. Statistical Analysis Used: Qualitative data were analyzed using Pearson's Chi-square test. Mann–Whitney U nonparametric test was used for statistically significant differences between the bacterial counts (median values and percent reduction) between the two groups and the Wilcoxon sign rank test for the intragroup evaluation of bacterial counts. Results: LSTR with TAP was found to be as effective as traditional indirect pulp treatment (P < 0.05). Conclusions: Minimal excavation and LSTR with TAP can be an effective treatment methodology for the management of deep carious lesions in primary molars.
Keywords: Deep carious lesions, lesion sterilization and tissue repair, minimal intervention, primary molars
|How to cite this article:|
Mittal M, Gupta N, Kumar A, Chopra R, Barua M. Clinical, microbiological, and radiographic evaluation of sealed carious dentin after minimal intervention in primary molars. J Indian Soc Pedod Prev Dent 2020;38:400-6
|How to cite this URL:|
Mittal M, Gupta N, Kumar A, Chopra R, Barua M. Clinical, microbiological, and radiographic evaluation of sealed carious dentin after minimal intervention in primary molars. J Indian Soc Pedod Prev Dent [serial online] 2020 [cited 2021 Jan 22];38:400-6. Available from: https://www.jisppd.com/text.asp?2020/38/4/400/306220
| Introduction|| |
Minimally invasive techniques for the treatment of carious lesions aim to prevent their progression and maintain pulp vitality by integrating principles of prevention, remineralization, and minimal intervention in the dental tissue. Management of deep carious lesions by selective or gradual removal of decayed tissue, as advocated in indirect pulp treatment (IPT), is advantageous over total removal of decayed tissue, since it allows the carious lesion to be arrested. The complete removal of carious dentin in these lesions may result in mechanical exposure of pulp and its bacterial invasion. In addition to the effective removal of carious tissue, timely and correct diagnosis, appropriate medication, and adequate restoration of the cavity are required for successful treatment.
Calcium hydroxide is the most commonly used agent in IPT of deep carious lesions. The standard clinical procedure consists of removing decomposed or infected dentin and leaving a layer of demineralized or affected dentin over which calcium hydroxide is applied and the tooth sealed. Calcium hydroxide stimulates odontoblasts to produce reparative dentin as well as kills microorganisms remaining in the thin layer of carious dentin left close to the pulp.
In continuation with the ultraconservative minimal intervention approach for carious lesions treatment, lesion sterilization and tissue repair (LSTR) is a novel concept of using antibacterial drugs to disinfect dentinal, pulpal, and periapical lesions. Once the lesions are disinfected or sterilized, they are repaired or regenerated by the host's natural recovery process. Softened dentin will re-calcify after sterilization, hence both softened (decomposed) and demineralized dentin can be left intentionally.
3Mix-MP triple antibiotic paste (TAP), a mixture of antibacterial drugs – metronidazole, ciprofloxacin, and minocycline with macrogol and propylene glycol, is found to be effective against oral bacteria, including when used for endodontic lesions of primary teeth. To avoid tooth staining due to minocycline, cefaclor can be used in its place.
The purpose of this study was to evaluate the clinical, radiographic, and microbiologic success rate of minimal excavation and LSTR with TAP for primary molars and compare it with calcium hydroxide IPT.
| Materials and Methods|| |
Sample size calculation
Following the literature survey, the expected mean ± standard deviation of bacterial count colony-forming units (CFU)/ml for group 1 was found to be 51.76 ± 57.50 and for the second group was 2.26 ± 4.26. For α error probability 5% and power (1-β error probability) 95% and effect size 1.2141259, the sample size was calculated to be 19 for each group.
The study was conducted in the department of pediatric and preventive dentistry. Children in the age group of 5–10 years, presenting to the departmental clinic for dental treatment, were screened, and those fulfilling the following inclusion criteria were considered for participation in the study.
Inclusion criteria for the study were: (1) healthy, co-operative dental patients aged 5–10 years; (2) clinically presenting deep carious lesion in primary molar without pulp exposure; (3) absence of clinical symptoms of irreversible pulpitis such as spontaneous pain or pain persisting after the disappearance of the existing stimulus or sensitivity to pressure; (4) absence of fistula, swelling in periodontal tissues, and abnormal tooth mobility; (5) radiographically, the radiolucency extending to more than half the thickness of dentin; (6) radiographic evidence of intact lamina dura; (5) absence of calcification in the pulp canal as determined by radiograph; (7) tooth restorable; (8) no evidence of furcation/inter-radicular pathosis or internal/external root resorption; and (9) during the operative procedures if a carious pulp exposure with obvious bleeding occurred, the tooth was excluded.
The study was approved by the institutional ethics committee. Informed consent was obtained from each patient's parents before enrolling them in the study.
Each child was randomly assigned to treatment groups A or B by the draw of lots method by the researcher who was blinded to the treatment methods. The two groups were: Group-A: (n = 20) Control – traditional Indirect pulp therapy using calcium hydroxide and Group-B: (n = 22) minimal excavation and LSTR with TAP, a mixture of ciprofloxacin (Ciplox-250, Cipla), metronidazole (Flagyl-400, Abbott), and cefaclor (Keflor-250, Ranbaxy) in 1:1:1 ratio by volume with macrogol and propylene glycol (glycerol).
Group-A: Local anesthesia administration and rubber dam isolation were done. The first clinical step was the preparation of the cavity and removal of undermined enamel from lateral walls of the carious lesion using high speed 330 number. diamond burs with copious water spray. Carious tissue at lateral walls of the cavity was completely removed with spoon excavators and/or tungsten carbide round burs at low speed.
After removing carious dentine from lateral walls, the cavity was washed with saline, dried with sterile swabs, and carious dentin sample was obtained from the cavity base with the help of a spoon excavator and sent for microbiologic analysis. The rest of the soft carious dentin at the base of the cavity was also removed with excavator until hard carious dentin was reached or pulp exposure occurred. The cavity was again washed with saline and dried with sterile swabs and the sample was taken with excavator/round bur (Excavabur, Dentsply, USA) at slow speed. The remaining hard carious dentin was covered with calcium hydroxide (Dycal, Dentsply, Milford DE, USA) and restored with resin-modified glass ionomer cement (RMGIC) (Fuji II LC, GC, Tokyo, Japan), followed by stainless steel crown (SSC).
Group-B: After rubber dam isolation, carious tissue from lateral walls of the cavity was completely removed as in Group-A. No further caries removal was done and the remaining soft infected dentine at the cavity floor was kept untouched. After washing the cavity with saline and drying with sterile swabs, the soft carious dentin sample was obtained from the cavity base with the help of a spoon excavator and sent for microbiologic analysis. The remaining layer of soft carious dentine was covered with TAP and sealed with a layer of RMGIC.
Cavity in Group B was re-entered after 6 weeks and carious dentin sample was taken again in the same manner with a spoon excavator and/or round carbide bur at slow speed (Excavabur, Dentsply, USA) and sent for microbiological evaluation. The tooth was again restored with RMGIC, followed by SSC.
Same size spoon excavator for taking carious dentin sample for microbiological evaluation was used in both the groups and volume of removed dentin was standardized through prior practice on extracted teeth. One pediatric dentist performed all pretreatment clinical and radiological examinations, treatments, and microbiologic samplings. Specimens collected were immediately transferred to 0.5 ml brain–heart infusion (BHI) broth and sent for microbiological processing.
Samples in BHI broth were vortexed for 60 s to break up the aggregates of bacteria. Mitis salivarious agar was used for the isolation and identification of Mutans streptococci (MS), and similarly Rogosa SL agar (RSL) was used for Lactobacilli sp. Mitis salivarius agar plates were incubated at 37°C for 48 h in a candle jar with 5% CO2 and RSL plates were incubated aerobically at 37°C for 48 h. Subsequently, the CFUs per plate were counted and the proportional reduction per sample was counted.
Clinical and radiological follow-up was done at 6 weeks, 3, 6, and 15–18 months intervals, and treatment success or failure was determined by a combination of clinical, microbiological, and radiographic findings by another pediatric dentist blinded to the treatment groups.
The clinical determinants of success were: (1) intact restoration; (2) lack of tooth mobility (unless associated with normal exfoliation); (3) lack of parulis; (4) no complaint of hot/cold sensitivity; and (5) lack of pain associated with the treated tooth (such as spontaneous pain or pain on percussion).
The radiographic criteria for treatment success were: (1) lack of periapical or interradicular pathology; (2) intact lamina dura; (3) intact restoration; and (4) lack of internal or pathological external root resorption.
The differences in both the groups for clinical, radiographic, and microbiologic (bacterial counts) parameters were statistically analyzed. Qualitative data (clinical and radiological evaluation) were analyzed using Pearson's Chi-square test. Mann–Whitney U nonparametric test was used for statistically significant differences between the bacterial counts (median values and percent reduction) between the two groups and the Wilcoxon sign rank test for the intragroup evaluation of bacterial counts.
| Results|| |
The total number of children who participated in Group A (Calcium hydroxide) was 20 out of which 9 (45%) were male and 11 (55%) were female. In Group B (TAP), total children were 22, of which 12 (54.5%) males and 10 (45.5%) females.
[Figure 1] shows the dropouts and failure cases at the follow-up visits for both the groups.
Clinical evaluation (Group A and B)
All 16 cases, excluding four children who missed appointments, from Group A were found to be clinically sound at the end of 15–18-month follow-up, whereas 19 cases out of 21 (excluding one who missed appointment) from Group B were successful clinically with only one patient complaining of nonlocalized mild sensitivity [Table 1] and [Figure 2].
|Table 1: Clinical evaluation of Groups A and B (Group A - calcium hydroxide, Group B - triple antibiotic paste)|
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|Figure 2: Graphical representation of clinical evaluation of both the groups|
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Other than 4 children who missed appointments, all 16 teeth were without any abnormality radiologically in Group A.
Out of 21 children in Group B (1 missed appointment at 15–18-month visit), two cases failed, one following internal resorption and another following periapical pathology. Nineteen teeth were found to be successful radiologically at 15–18-month follow-up [Table 2] and [Figure 3].
|Table 2: Radiological evaluation of Groups A and B (Group A - calcium hydroxide, Group B - triple antibiotic paste)|
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|Figure 3: Graphical representation of radiographic evaluation of both the groups|
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Intergroup comparison: The median value of both MS and lactobacilli microorganisms in Group A at postexcavation was significantly higher than Group B at 6 weeks, P = 0.000 (P < 0.001) and P = 0.001 (P < 0.05) [Table 3] and [Figure 4].
|Table 3: Microbiological evaluation of Groups A and B (Group A - calcium hydroxide, Group B - triple antibiotic paste)- intergroup evaluation by Mann-Whitney U-test and intragroup with Wilcoxon sign rank test|
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|Figure 4: Mean count (Log10 [CFU + 1]) of mutans streptococci and lactobacilli at baseline and at 6 weeks/postexcavation|
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The percentage reduction of MS and lactobacilli from baseline to postexcavation/6 weeks was significantly higher in Group B than Group A, (P < 0.001) [Table 4] and [Figure 5].
|Table 4: Comparison of percentage reduction of mutans streptococci Log10 (colony-forming unit+1) and lactobacilli Log10 (colony-forming unit+1) from baseline between two groups by Mann-Whitney U-test|
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|Figure 5: Percentage reduction of log10 (CFU + 1) count of mutans streptococci and lactobacilli in both the groups|
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Intra group comparison: The median value of MS and Lactobacilli in group A from baseline to postexcavation was significantly reduced, P = 0.009 (P < 0.05) and P = 0.002 (P < 0.05), respectively. The median value of MS and lactobacilli in Group B from baseline to 6 weeks was significantly reduced, P = 0.000, (P < 0.001) and P = 0.000 (P < 0.001), respectively [Table 3] and [Figure 4].
| Discussion|| |
Successful treatment outcome of deep carious lesions requires timely and correct diagnosis, effective removal of carious dentin, use of appropriate medications, and adequate restoration of the cavity. Medication used in Group A was calcium hydroxide and in Group B, TAP of metronidazole, ciprofloxacin, and cefaclor with macrogol-propylene glycol. TAP contains both bactericidal (metronidazole and ciprofloxacin) and bacteriostatic (minocycline) components. Minocycline causes tooth discoloration and cefaclor has been proposed as possible alternative to minocycline in terms of its antibiotic effectiveness. TAP has been extensively used in endodontics as an intracanal medicament for the treatment of periapical lesions. Very few studies have been reported for its usage in restorative dentistry. Yesilyurt et al. demonstrated that the addition of 1.5% TAP to GIC does not modify the physical and bonding properties, the compressive strength, and maintains optimal bond strength to dentine. In their in vitro study, they found GIC containing TAP to be quite effective on Streptococcus mutans and Lactobacillus casei. In another study, Trairatvorakul and Sastararuji successfully used 3Mix-MP for deep carious lesions after removing carious dentine on the surrounding walls and leaving the remaining soft infected dentine at the cavity floor untouched.
RMGIC was used for restoration as resin added to conventional GICs improves their physical properties and bonding characteristics. Pulpal tolerance of resin-modified GICs is similar to that of conventional GICs. Following RMGIC restoration, the tooth was further restored with SSC. SSC is the treatment of choice for extensive carious lesions in primary teeth as it is durable, has long life span, protects the remaining tooth structure adequately, and prevents marginal leakage.
The present treatment approach was based on the recommendation that re-entering the cavity to remove demineralized dentin is not necessary in primary teeth as they have a limited life span. Furthermore, reopening the cavity and removal of remaining carious dentin may injure the pulp, increases the risk of pulp exposure, and adds additional cost, time, and discomfort to the patient.,, In TAP group, re-entry was done to take microbiological sample but no further removal of carious dentin was done. During re-entry in most of the cases, the dentin sample could not be obtained with a spoon excavator and round carbide bur (Excavabur) had to be used to extract the sample. Although properties of dentin were not histologically evaluated in our study, the change in consistency could be visibly appreciated in these cases.
Clinical and radiological success at 15–18 months with microbial count reduction was observed with incomplete carious dentin removal in both Group A-calcium hydroxide IPT and Group B-TAP LSTR.
In our study, the overall success rate for Group A-calcium hydroxide IPT till 15–18 months recall, both clinically and radiologically was higher than Group B-TAP LSTR, but the difference was not statistically significant. Similar results have been reported by Trairatvorakul and Sastararuji, though in their study during calcium hydroxide IPT, carious dentin was removed till a layer of soft carious dentin was left, while it was removed till hard carious dentin in our study.
The role of adequate coronal seal or intact restoration cannot be overemphasized. The lack of intact restoration leads to failure of the procedure of calcium hydroxide IPT. In case of TAP-LSTR also, there was one case of lack of marginal seal of the restoration, but the patient reported immediately and treatment could be continued.
There were two cases of failure in the TAP-LSTR group. This could be due to a higher rate of progression of caries than the antibacterial sterilization rate of TAP. It could also be because of misdiagnosis of the pulpal condition. One failure was detected clinically as the patient complained of pain during mastication and was also seen radiologically, while other could be detected radiologically only. Farooq et al. and Trairatvorakul and Sastararuji stated that all clinical failures exhibited radiological failure, but not all radiological failures have clinical signs and symptoms. A similar finding was observed in our study.
The incomplete removal of carious dentin till hard carious dentin in calcium hydroxide IPT group or sealing with TAP without removal of carious dentin at cavity base, both resulted in substantial reduction of bacterial counts of MS and lactobacilli. This led to decelerating the progression of lesion and promoting physiologic reaction in the pulp dentin complex. Thus, both methods can be considered effective for bacterial count reduction. In Group A, after removal of caries till hard dentin was reached, bacterial growth was still detected (percentage reduction was 25.3%). This finding is consistent with other studies, which indicated that though total counts were largely reduced, some bacteria always persisted in clinically caries-free dentin.,,
Statistically significant higher reduction in counts was seen in the TAP group as compared to the calcium hydroxide group for both MS and lactobacilli. This could be because of the antibacterial effect of TAP in Group B, whereas in Group A, the carious dentin sample was taken after removal of carious dentin till hard carious dentin without application of calcium hydroxide. Thus, the antibacterial effect of the calcium hydroxide group could not be compared with TAP in the present study. Many studies are available in literature recommending TAP for disinfection of severely infected root canals,, while only one study is available regarding antibiotic sterilization in IPT, but in that also, only clinical and radiological success rate is evaluated and no microbiological evaluation is done.
There are certain limitations to the use of TAP in the routine management of deep carious lesions as unlike calcium hydroxide, it is not available as a commercial product and each antibiotic can be stored for 1 month only after being pulverized into powder. Once it is mixed with macrogol and propylene glycol, it must be used within a day., Another limitation of TAP is that it cannot be used in patients who are sensitive to the drugs.
LSTR with TAP can be used as an alternative to calcium hydroxide IPT as it has an added advantage of being an ultraconservative procedure which requires no removal of infected dentin at the base of the cavity, thus preserving more tooth structure. LSTR does not require local anesthesia administration also which can be of benefit in uncooperative or lacking cooperative ability children.
| Conclusions|| |
- The clinical and radiographic outcomes of minimal excavation and LSTR with TAP were similar to calcium hydroxide indirect pulp therapy
- The microbiological counts were found to be significantly reduced after 6 weeks of lesion sterilization even with minimal removal of carious tissue.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4]