Lesion Sterilization and Tissue Repair Antibiotic Paste Versus Zinc Oxide and Eugenol Pulpectomy for Treatment of Primary Molars With Pulp Necrosis
Phase: PHASE1
Conditions: Pulp Necrosis
Sponsor: University of Faisalabad

 
LESION STERILISATION AND TISSUE REPAIR 
ANTIBIOTIC PASTE VERSUS ZINC OXIDE AND EUGENOL 
PULPECTOMY FOR TREATMENT OF PRIMARY MOLARS 
WITH PULP NECROSIS 
 
 
 
 
 
 
 
Dated : 31st  May, 2025 
 
 

 
INTRODUCTION: 
Severe carious lesions on primary teeth frequently lead to infectious changes in the dental pulp, 
due to the thinner and more porous calcified dentin and the reduced protective ability of the 
dentin-pulp complexes. The main diagnoses of dental pulp disorders encompassed chronic 
hypertrophy, purulent gangrenous variants, and necrotic forms1. Pulpal infections occur more 
rapidly in primary teeth due to their distinct form and structure compared to permanent teeth2. 
Teeth that are pathological, have considerable surface deterioration, lack sufficient bone 
support, and demonstrate extensive root resorption are frequently considered for extraction. 
The premature loss of teeth results in several complications, including the displacement of 
neighboring teeth, interruption of the normal eruption sequence, insufficient room for 
permanent teeth, alterations in speech, and diminished usefulness3,4. TA substitute to extraction 
is endodontic treatment, sometimes known as pulpectomy. Pulpectomy of necrotic primary 
molars is a considerable challenge in juvenile dental clinics. The intricacy of root canal 
anatomy and the protracted duration of therapy are the principal concerns. Moreover, 
endodontic therapy in juvenile patients requires their cooperation. The increased challenge in 
detecting root resorption limits the precise determination of the actual working length5. 
Simpler methods utilizing antibiotic pastes have been recommended in mainstream clinical 
practice due to the limitations of primary tooth root canal preparation. Without preparing the 
canal, these pastes are placed to the pulp chamber floor3. Necrotic primary teeth have been 
treated with zinc oxide and eugenol (ZOE) paste since 1930. Radiopacity, tissue compatibility, 
and antibacterial properties define ZOE paste. ZOE endodontics provides outstanding 
radiological and clinical results5. A new, less-invasive, more effective approach may give 
physicians and patients hope. Lesion sterilization and tissue repair (LSTR) supports numerous 
therapeutic uses. The goal is to eliminate pulp germs with a simpler way. The LSTR treatment 
technique focused on restoring primary teeth with a particular antibiotic combination. 
Antibacterial paste targets several microorganisms. The LSTR approach validated on major 
teeth with multiple roots yielded good prognostic findings. This reduces or eliminates clinical 
and radiographic symptoms without preventing permanent tooth formation1. When extraction 
or pulpectomy is not possible due to a poor prognosis, lesion sterilization and tissue healing 
are ideal4–8. In one research, the effectiveness of ZOE pulpectomy and LSTR antibiotic paste 

in treating necrotic primary molars was examined. After six months, the effectiveness in terms 
of overall success was 23 (52.3%) in ZOE and 32 (72.7%) in LSTR5.  
The management of necrotic primary teeth remains a subject of debate, with no established 
consensus on the optimal endodontic procedure or restorative material. This study is designed 
to compare the effectiveness of ZOE pulpectomy with the LSTR technique using a triple 
antibiotic paste in primary molars affected by pulp necrosis. The findings aim to identify the 
superior treatment approach, thereby enhancing tooth retention and minimizing the risk of early 
tooth loss and postoperative complications. 
OBJECTIVE: 
To compare the efficacy of lesion sterilization and tissue repair antibiotic paste versus ZnO and 
Eugenol pulpectomy for treatment of Primary molars with Pulp Necrosis 
OPERATIONAL DEFINITION: 
 
Pulp Necrosis: will be identified radiographically by the presence of a radiolucent area in the 
furcation or periapical region, loss of lamina dura, or widening of the periodontal ligament 
space on intraoral periapical radiographs.  
Efficacy: Each tooth will be labeled with its overall success, which will include only those 
who passed both clinical and radiographic examinations after six months.  Clinical success will 
be defined as the absence of nasal tract edema and/or peeling.  Radiographic success criteria 
will include the initial radiolucent region being missing, reduced in size, or completely 
vanishing, as well as the lack of any new radiolucency. 
HYPOTHESIS: 
Null Hypothesis 
There is no difference in the efficacy of LSTR antibiotic paste versus ZOE for treatment of 
Primary molars with Pulp Necrosis. 
Alternate Hypothesis 
There is a difference in the efficacy of LST antibiotic paste versus ZOE for treatment of Primary 
molars with Pulp Necrosis 
 

MATERIAL AND METHODS: 
 
Study design: Randomized Controlled Trial. 
Study setting: Department of Operative Dentistry, MTH, Faisalabad. 
Duration of study: 
1 year after synopsis approval 
Sample size:  
By using WHO calculator for two proportions at 
Significance level (α)  
= 
 
5% 
Power of test  
 
= 
 
80% 
Proportion in Group A(p1)  
= 
 
72.70%5 
Proportion in Group B (p2)  = 
 
52.30%5 
Sample size 
 
 
= 
 
180 (90 in each group) 
Sampling Technique: Non-Probability Consecutive Sampling.  
SAMPLE SELECTION 
Inclusion criteria: 
• Children of both genders 
• 4 years and 10 years 
• Pulp necrosis in mandibular primary molars with minimum of 2/3 of the roots 
• Consent from Parents/Guardian of children. 
• Sufficient crown structure for restoration. 
 
Exclusion criteria: 
• Children who have a physical or mental change. 
• Involving systemic illnesses. 
• History of allergy to drugs being utilized 
• Antibiotics use within three months 
• Teeth with aberrant root resorption or pulp canal obliteration on periapical 
radiography 
 
 

Data collection procedure: 
After receiving ethical permission from CPSP and The University of Faisalabad's ERB, this 
project will start. Once their guardians have given their verbal approval, eligible patients will 
be registered. Pulp necrosis will be diagnosed using a predetermined operational definition. 
Using a straightforward random table, patients will be divided into two groups at random. The 
lead researcher will carry out every process. We'll employ standard behavior control strategies. 
Local anesthesia will be administered after topical anesthetic (2% lignocaine gel). Following 
rubber dam isolation, normal procedures will be used to remove soft caries and open the access. 
• Group A (LSTR): After chamber irrigation with 3% NaOCl and drying, CTZ paste 
(chloramphenicol, tetracycline, zinc oxide mixed with eugenol) will be prepared from 
encapsulated powders and applied to the pulp chamber. The cavity will be restored with 
resin-modified glass ionomer cement. 
• Group B (ZOE Pulpectomy): Following working length determination via radiograph, 
canal debridement will be performed using K-files and 3% NaOCl. ZOE paste will be 
prepared from encapsulated ZnO mixed with eugenol and placed manually in canals, 2 
mm short of the apex. Final restoration will be with resin-modified glass ionomer. 
At six months, patients will have a clinical and radiological evaluation. By collecting the 
patients' mobile numbers, follow-up will be guaranteed. After six months, efficacy will be 
noted in both clinical and radiographic studies. The lack of nasal tract edema and/or peeling 
will be considered a clinical success. Success in radiography will be determined by whether 
the original radiolucent region is gone, shrinks in size, or vanishes completely, as well as by if 
no new radiolucency appears. 
Data analysis: 
SPSS version 25.0 will be used to analyze the data. Frequencies and percentages will be used 
to display categorical factors such gender, radiolucency, edema, root resorption, tooth mobility, 
and treatment effectiveness. The mean ± standard deviation will be used to represent the 
continuous variable, age. The effectiveness of the two groups' treatments will be compared 
using the Chi-square test. To manage their impact, stratification will be carried out for effect 
modifiers such as age, gender, and bone crypt involvement. A p-value of less than 0.05 will be 
regarded as statistically significant in the post-stratification chi-square test. 
 
 

References: 
1. Zukanović A, Bajrić E, Marković N, Duratbegović D, Katana E, Čengić E, et al. Lesion 
sterilization and tissue repair (LSTR) method in irreversible dental pulp changes of 
primary teeth. Balkan J Dent Med. 2023;27(1):15-20. 
2. Shankar K, Ramkumar H, Dhakshinamoorthy S, Paulindraraj S, Jayakaran TG, 
Bommareddy CS. Comparison of Modified Triple Antibiotic Paste in Two 
Concentrations for Lesion Sterilization and Tissue Repair in Primary Molars: An In 
Vivo Interventional Randomized Clinical Trial. Int J Clin Pediatr Dent 2021;14(3):388–
392. 
3. Garrocho-Rangel A, Jalomo-Ávila C, Rosales-Berber MÁ, Pozos-Guillén A. Lesion 
Sterilization Tissue Repair (LSTR) approach of non-vital primary molars with a 
chloramphenicol-tetracycline-ZOE antibiotic paste: A scoping review. J Clin Pediatr 
Dent. 2021;45(6):369-75. 
4. Sefa I, Garg N, Pathivada L, Yeluri R. Success of Lesion Sterilization and Tissue Repair 
Therapy and Pulpectomy in the Management of Infected Primary Molars with Poor 
Prognosis. Int J Clin Pediatr Dent 2024;17(1):41–47 
5. Moura J, Lima M, Nogueira N, et al. LSTR antibiotic paste versus zinc oxide and 
eugenol pulpectomy for the treatment of primary molars with pulp necrosis: A 
randomized controlled trial. Pediatr Dent 2021; 43(6):435-42. 
6. Castro M, Lima M, Lima C, Moura M, Moura J, Moura L. Lesion sterilization and 
tissue repair with chloramphenicol, tetracyline, zinc oxide/eugenol paste versus 
conventional pulpectomy: A 36-month randomized controlled trial. Int J Paediatr Dent. 
2023;33(4):335-45. 
7. Duarte ML, Pires PM, Ferreira DM, Pintor AV, de Almeida Neves A, Maia LC, et al. Is 
there evidence for the use of lesion sterilization and tissue repair therapy in the 
endodontic treatment of primary teeth? A systematic review and meta-analyses. Clin 
Oral Invest. 2020; 24:2959-72. 
8. Shetty AA, Geethanjali G, Hegde AM. Lesion sterilization and tissue repair in primary 
teeth. SRM J Res Dent Sci. 2020; 11(2):99-105. 
 
 
 
 
 
 
 
 
 
 

DATA COLLECTION PROFORMA 
 
“LESION STERILISATION AND TISSUE REPAIR ANTIBIOTIC PASTE VERSUS 
ZINC OXIDE AND EUGENOL PULPECTOMY FOR TREATMENT OF PRIMARY 
MOLARS WITH PULP NECROSIS”  
Case No:   
 
 
 
Hospital Registration:  
 
 
Date:   
ID:  
 
 
 
 
 
 
Age:    
Gender: M □  F □  
 
Group:  
Group A/Group B 
CLINICAL 
 
Pre-Operative 
24 Hours 
3 Months 
6 Months 
Yes 
No 
Yes 
No 
Yes 
No 
Yes 
No 
Mobility 
 
       
 
 
 
 
 
 
Sinus 
tract/Abscess 
 
 
 
 
 
 
 
 
Clinical 
success 
 
 
 
 
 
 
 
 
 
RADIOGRAPHIC 
 
Pre-
Operative 
24 Hours 
3Months 
6 Months 
Yes 
No 
Yes 
No 
Yes 
No 
Yes 
No 
Furcation 
radiolucency 
 
 
 
 
 
 
 
 
Peri-apical 
radiolucency 
 
 
 
 
 
 
 
 
Radiographic 
success 
 
 
 
 
 
 
 
 
 
 
 
 

Key: 
Yes 
↑ = Increase  
No 
↓ = Decrease 
↔ = Stable 
A= Absent 
 
Main Outcome Variable 
Total Efficacy: Yes/No