Successful endodontic treatment in young permanent teeth with necrotic pulp is highly dependent on the complete elimination of microbial infection from the root canal system (1). The presence of persistent bacteria within the root canal is a major challenge, as it can lead to treatment failure and periapical pathology (2). Therefore, the use of effective intracanal medicaments plays a crucial role in disinfecting the root canal and preventing reinfection before final obturation (3).

Several intracanal medicaments have been introduced to enhance microbial elimination, with calcium hydroxide (Ca(OH)₂) being the most commonly used due to its high alkalinity and ability to inactivate bacterial endotoxins (4). However, its effectiveness against certain resistant bacterial species, such as Enterococcus faecalis, has been questioned (5). Alternatively, triple antibiotic paste (TAP), which contains a combination of ciprofloxacin, metronidazole, and minocycline, has been reported to be highly effective against endodontic pathogens (6). Another widely used medicament is chlorhexidine (CHX), a broad-spectrum antimicrobial agent with substantivity that enhances bacterial eradication within the root canal (7).

Although numerous studies have evaluated the antimicrobial properties of individual intracanal medicaments, limited in vivo research compares their efficacy in young permanent teeth with necrotic pulp (8). This study aims to assess and compare the antimicrobial effectiveness of Ca(OH)₂, TAP, and CHX as intracanal medicaments by evaluating bacterial reduction following their application. The findings of this study may provide clinical insights into the most effective medicament for endodontic disinfection in young permanent teeth.

Study Design and Sample Selection

This in vivo study was conducted on 60 young permanent teeth diagnosed with necrotic pulp and apical periodontitis in patients aged 8 to 14 years. Ethical approval was obtained from the institutional review board, and written informed consent was obtained from the patients’ guardians before participation. The included teeth had fully formed roots with radiographic evidence of periapical lesions and no history of prior endodontic treatment. Teeth with root fractures, resorption, or systemic conditions affecting healing were excluded from the study.

Grouping and Treatment Protocol

The selected teeth were randomly divided into three groups (n=20) based on the intracanal medicament used:

• Group A: Calcium hydroxide (Ca(OH)₂)
• Group B: Triple Antibiotic Paste (TAP) (ciprofloxacin, metronidazole, minocycline)
• Group C: 2% Chlorhexidine (CHX) gel

Clinical Procedure

Local anesthesia was administered, and rubber dam isolation was performed. Access cavity preparation was done using a high-speed diamond bur under water coolant. Working length was determined using an electronic apex locator and confirmed radiographically. Initial debridement was performed using 5.25% sodium hypochlorite (NaOCl) and saline irrigation.

Pre-medication microbial samples were collected from the root canal using sterile paper points, which were transferred into transport media and cultured on brain heart infusion (BHI) agar for bacterial count analysis. Following sample collection, the respective intracanal medicaments were placed in the root canals using a lentulo spiral, and the access cavity was sealed with temporary restorative material. The medicaments were left in place for 14 days.

Microbial Assessment

After the intervention period, post-medication microbial samples were collected using the same technique as before. The samples were incubated, and colony-forming units (CFUs) were recorded to evaluate bacterial reduction. The percentage decrease in bacterial load was calculated for each group.

Statistical Analysis

The collected data were analyzed using SPSS software (version XX.X). The normality of the data was assessed using the Shapiro-Wilk test. A one-way ANOVA test was used to compare the mean bacterial reduction among the three groups, followed by post hoc Tukey’s test for pairwise comparisons. A p-value of <0.05 was considered statistically significant.

A total of 60 young permanent teeth with necrotic pulp were evaluated for bacterial reduction following the application of different intracanal medicaments. The pre-medication microbial analysis showed comparable bacterial counts among the three groups. After 14 days of intracanal medicament application, all groups exhibited a significant reduction in bacterial load (p < 0.05).

Group B (Triple Antibiotic Paste) demonstrated the highest bacterial reduction (92%), followed by Group C (Chlorhexidine Gel) at 85%, and Group A (Calcium Hydroxide) at 78% (Table 1). The ANOVA test showed a statistically significant difference among the groups (p = 0.003). Pairwise comparisons using post hoc Tukey’s test indicated that the reduction in bacterial load was significantly greater in Group B compared to Group A (p = 0.002) and Group C (p = 0.01), whereas the difference between Group A and Group C was not statistically significant (p = 0.08).

(Table 1) illustrates the mean CFU counts before and after intracanal medication application, highlighting the significant antimicrobial efficacy of Triple Antibiotic Paste (TAP) over Calcium Hydroxide and Chlorhexidine Gel. ​​

Table 1: Antimicrobial Efficacy of Intracanal Medicaments

microbial infection from the root canal system. The present study compared the antimicrobial efficacy of Calcium Hydroxide (Ca(OH)₂), Triple Antibiotic Paste (TAP), and Chlorhexidine Gel (CHX) in young permanent teeth with necrotic pulps. The findings demonstrated that TAP exhibited the highest bacterial reduction (92%), followed by CHX (85%) and Ca(OH)₂ (78%). These results align with previous studies emphasizing the superior antimicrobial potential of TAP over conventional intracanal medicaments (1,2).

Ca(OH)₂ has been widely used in endodontic therapy due to its high alkalinity (pH ~12.5) and ability to neutralize bacterial endotoxins (3). However, its antibacterial effect is limited against Enterococcus faecalis and Candida albicans, which are commonly associated with persistent endodontic infections (4,5). The results of the present study showed a 78% bacterial reduction with Ca(OH)₂, which is consistent with prior research highlighting its effectiveness but also its limitations in cases with resistant bacterial strains (6,7).

TAP, a combination of ciprofloxacin, metronidazole, and minocycline, demonstrated the highest bacterial reduction in this study (92% reduction in CFU count). The broad-spectrum antibacterial properties of TAP allow it to target both aerobic and anaerobic microorganisms, making it particularly effective in cases of polymicrobial root canal infections (8). Studies have reported that TAP is highly effective in eliminating E. faecalis, Porphyromonas gingivalis, and Prevotella intermedia, which are frequently found in infected root canals (9,10). However, concerns have been raised regarding the risk of tooth discoloration due to minocycline and its potential cytotoxic effects on stem cells in regenerative endodontics (11).

Chlorhexidine (CHX) is a well-documented antimicrobial agent with broad-spectrum activity and substantivity that enhances its long-term effect in root canal disinfection (12). The present study observed an 85% bacterial reduction with CHX, which is in agreement with previous research supporting its superior efficacy over Ca(OH)₂ but slightly lower than that of TAP (13). CHX has been shown to be effective against E. faecalis due to its ability to disrupt bacterial cell walls and inhibit biofilm formation (14). However, it lacks the tissue-dissolving ability of NaOCl and may lead to potential precipitation reactions when used with other irrigants (15).

The statistical analysis in this study confirmed a significant difference in bacterial reduction among the three groups (p < 0.05), with TAP showing the most superior antimicrobial effect. Similar findings have been reported in various studies comparing intracanal medicaments in young permanent teeth, further supporting the use of TAP as a highly effective option for endodontic disinfection (16,17). However, given the potential drawbacks of TAP, including tooth discoloration and possible bacterial resistance, alternative formulations such as modified TAP (without minocycline) or calcium hydroxide combinations with CHX have been proposed to enhance antimicrobial efficacy while minimizing adverse effects (18,19).

One of the limitations of this study is its short-term evaluation of bacterial reduction, as microbial regrowth may occur over time if the medicament does not completely eradicate all bacterial species. Additionally, only aerobic culture methods were used, which may not have fully captured the complex polymicrobial nature of root canal infections. Future studies should incorporate molecular techniques such as polymerase chain reaction (PCR) and next-generation sequencing (NGS) to provide a more comprehensive analysis of bacterial diversity and persistence following intracanal medication (20,21).

The findings of this study contribute to the growing body of evidence supporting the selection of intracanal medicaments based on their antimicrobial potential, clinical applicability, and safety. TAP remains a highly effective choice for root canal disinfection, but its clinical limitations warrant further investigation into alternative formulations

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