New Technique for Smear Layer Removal in Endodontics

Title: A Novel Approach in Endodontic Smear Layer Removal Using Nano and Submicron Diamonds

This presentation explores an innovative method for enhancing the effectiveness of smear layer removal during root canal treatment. Traditional irrigants like EDTA and Sodium Hypochlorite, while effective, present challenges such as dentin erosion and reduced antimicrobial efficacy when combined. This presentation introduces the use of nano and submicron diamond particles, activated by sonic and ultrasonic irrigation, as a potential solution. The slides delve into the chemical interactions, effectiveness, and limitations of both traditional and novel approaches, backed by recent research and studies. This comprehensive overview is designed for dental professionals seeking to improve clinical outcomes in endodontics through cutting-edge techniques.

1. A Novel Endodontic Approach in Removing Smear Layer Using Nano and Submicron Diamonds with Intracanal Oscillation Irrigation Ching-Shuan Huang et al .

2. CONTENTS INTRODUCTION AIM OF THE STUDY METHODOLOGY STATISTICAL ANALYSIS RESULTS DISCUSSION S.W.O.C ANALYSIS CONCLUSION REFERENCES

3. INTRODUCTION A surface film of debris retained on dentin and other surfaces after instrumentation with either rotary instruments or endodontic files; consists of dentin particles, remnants of vital or necrotic pulp tissue, bacterial components and retained irrigant Following the process, the root canal has to be obturated to prevent bacterial ingress Presence of a smear layer on the surface of root canals affects the sealing ability is controversial

4. INTRODUCTION E ndodontic success rates increase with the presence of a smear layer since the smear layer can obstruct dentinal tubules, preventing bacterial exchange S mear layer can nourish bacteria and cause the proliferation of microorganisms

5. INTRODUCTION S mear layer acts as a barrier that hinders the penetration of intracanal medicaments into dentinal tubules Improved retention and better sealing ability are demonstrated with the mechanical interlocking of the sealer plug in dentinal tubules

6. INTRODUCTION C omplete debridement of the smear layer is crucial for successful root canal treatment

7. INTRODUCTION Ethylenediamine tetra-acetic acid HOW TO REMOVE SMEAR LAYER? [CH 2 N(CH 2 CO 2 H) 2 ] 2 Removes the inorganic component of smear layer Carboxylate (–COO⁻) groups Amine (–NH₂) groups Tightly binds with calcium ions in the dentin (Forms a stable complex)

8. INTRODUCTION Ethylenediamine tetra-acetic acid HOW TO REMOVE SMEAR LAYER? [CH 2 N(CH 2 CO 2 H) 2 ] 2 Tightly binds with calcium ions in the dentin Calcium ions bound to EDTA become part of soluble compound called – Calcium Chelate Easily washed away, effectively removing the smear layer that contains these calcium deposits.

9. INTRODUCTION Ethylenediamine tetra-acetic acid DISADVANTAGES OF EDTA [CH 2 N(CH 2 CO 2 H) 2 ] 2 Calcium Depleting Dentinal Erosion Demineralisation Reduced Dentin Microhardness

10. INTRODUCTION SODIUM HYPOCHLORITE [ NaOCl ] Removes the organic component of smear layer Bactericidal / dissolves organic matter & necrotic tissue Physically flushes out debris (Saponification) Provides haemostasis

11. INTRODUCTION SODIUM HYPOCHLORITE + EDTA AS AN IRRIGANT NaOCl when used as a final irrigant after EDTA leads to chemical erosion of root canal walls NaOCl + EDTA leads to loss of Free Available Chlorine (FAC) which leads to lowered tissue dissolution ability

12. INTRODUCTION ETIDRONATE (HEBP) Continuous chelating irrigant – maintains proteolytic and antimicrobial properties of NaOCl 1 HYDROXYETHYLIDENE-1, 1- BISPHOSPHONATE ADVANTAGES Soft chelator (minimal demineralizing effects on dentin) Dissolves inorganic tissue without disrupting the action of NaOCl Has a beneficial impact on the bond strength of epoxy based sealers to dentin

13. INTRODUCTION IRRIGATION METHODS Efficiency of root canal irrigation depends on Delivery System Properties of the Irrigant Traditional irrigation delivery systems are inefficient to achieve complete cleanliness of canal Advanced irrigation systems include Sonic Activator Ultrasonic Activator

14. INTRODUCTION IRRIGATION METHODS Sonic Activator Ultrasonic Activator Flexible Tips : Sonically driven systems use flexible tips to increase intracanal fluid flow and reach curved and apical portions of the canals more effectively. Advantages : Easier access to curved canals and improved fluid flow within the canal system. PUI uses a stainless steel file to oscillate the irrigation solution within the canal without simultaneous instrumentation. Benefits : Promotes cleanliness of the root canals by enhancing fluid movement through cavitation and acoustic microstreaming Limitations : Rigid ti p / ineffective cleaning in curved canals / risk of ledges / perforations

15. INTRODUCTION NANOPARTICLES IN BACTERIOSTATIC RESEARCH Studied for their anti-bacteriostatic effect

16. INTRODUCTION NANOPARTICLES IN BACTERIOSTATIC RESEARCH Silver Nanoparticles Chitosan Nanoparticles Diamond Nanoparticles Iron Oxide Nanoparticles

17. INTRODUCTION SMEAR LAYER REMOVAL FROM APICAL 1/3 RD There is no physical method to achieve the goal of smear layer removal, especially in the apical third of the root canal. It’s purely CHEMICAL

18. AIM OF THE STUDY E valuate the effectiveness of nano and submicron diamond solution with sonic or ultrasonic oscillation on smear layer removal.

19. MATERIALS & METHODS 80 Exclusion Criteria Under 18 years Open Apex Previously RC treated tooth Severe RC infection 80 freshly extracted single rooted premolars

20. INSTRUMENTATION OF TEETH SPECIMENS Access Cavity Preparation Establishing Glide Path Biomechanical Preparation Irrigation & Drying Pulp chambers accessed using a round diamond bur in a high-speed handpiece. Preliminary shaping with #10 k-file and recording of working lengths. Used ProGlider ® Rotary Glide Path File (size 16, 0.02 taper) and ProTaper ® Gold SX file. Sequence of Files : S1 : Size 18, 0.02 taper S2 : Size 20, 0.04 taper F1 : Size 20, 0.07 taper F2 : Size 25, 0.08 taper Irrigated canals with 5 mL of 3% NaOCl after each rotary file. Canals dried with paper points after final preparation.

21. PREPARATION OF NANO AND SUBMICRON DIAMONDS Nano-diamond Source Test Groups Characterization Commercially sourced from HonWay Materials Co., Ltd., Kaohsiung, Taiwan. Synthesized using a high-pressure, high-temperature process. Five different sizes of nanodiamonds selected: 10 nm, 50 nm, 100 nm, 500 nm, and 1000 nm . Purity and particle size distributions confirmed using a Particle Size Analyzer (LA-920, HORIBA, Fukuoka, Japan).

22. ROOT CANAL IRRIGATION SOLUTIONS Irrigation Solution Groups [1] Control – 3% NaOCl [2] + ve Control – 17% EDTA [3] - ve Control – Distilled Water [4] - 3% NaOCl + 10 nm nanodiamonds (10 mg/mL) [5] - 3% NaOCl + 50 nm nanodiamonds (10 mg/mL) [6] - 3% NaOCl + 100 nm nanodiamonds (10 mg/mL) [7] - 3% NaOCl + 500 nm submicron diamonds (10 mg/mL) [8] - 3% NaOCl + 1000 nm submicron diamonds (10 mg/mL)

23. SONIC AND ULTRASONIC VIBRATION OSCILLATION Irrigation Solution Delivery Oscillation Procedure Post-Oscillation Solutions delivered into prepared teeth with a 30-gauge syringe needle, inserted 1 mm short of the working length. Each group (5 samples per group) oscillated separately for 10 seconds. Ultrasonic Irrigation : Performed using Newtron P5 ( Satelec , France). Equipped with a metal blunt working-end tip Sonic Irrigation : Applied using EndoActivator (Dentsply Sirona, USA). Used with a disposable polymer tip. All specimens were irrigated with 3 mL of distilled water. Specimens were then dried with sterile paper points.

24. SCANNING ELECTRON MICROSCOPY (SEM) ANALYSIS Specimen Preparation SEM Imaging Crown portion of each tooth cut off under a dental operating microscope ( Extaro 300, Zeiss, Germany). Specimens dehydrated and processed with gold palladium. Viewed under a scanning electron microscope (SU3500, Hitachi, Japan) at 500x and 2000x magnifications. Aim was to examine the remaining smear layer and dentinal tubule exposure. Roots sectioned perpendicularly into coronal, middle, and apical thirds using a low-speed diamond disc.

25. SCANNING ELECTRON MICROSCOPY (SEM) ANALYSIS Smear Layer Evaluation Observer Calibration & Evaluation Based on Hulsmann et al.’s four-point scale: Score I : Dentinal tubules completely opened. Score II : More than 50% of dentinal tubules opened. Score III : Less than 50% of dentinal tubules opened. Score IV : All dentinal tubules covered with smear layer. Two calibrated observers performed a blind evaluation of SEM images. Agreement between observers assessed using the kappa test.

26. STATISTICAL ANALYSIS Tests Used Data Analysis Kruskal–Wallis Test : to evaluate statistical differences across multiple groups. Mann–Whitney U Test : for pairwise comparisons between groups. Mean scores from the coronal, middle, and apical thirds were analyzed. Results with p < 0.05 were considered statistically significant.

27. RESULTS (Smear Layer Removal through Sonic Oscillation) Control Control group 1 (3% NaOCl ) had the most ineffective smear layer removal in all sections Nano/Submicron Diamond Groups Comparison with EDTA 10nm Diamonds Effective removal : 50 nm, 100 nm, 500 nm, 1000 nm diamonds showed dentinal tubule exposure similar to the EDTA group Fragmentation : Larger diamond sizes (e.g., 1000 nm) left larger fragments on the root canal wall No significant difference in coronal and middle thirds between EDTA and 50 nm, 100 nm, 500 nm, 1000 nm diamonds. EDTA more effective in apical third Did not show significant improvement over NaOCl and distilled water groups.

28. RESULTS (Smear Layer Removal through Ultrasonic Oscillation) Effectiveness of Diamond Solutions Comparison with EDTA Overall Findings Significant Removal : 500 nm and 1000 nm submicron diamond solutions showed significant smear layer removal. Exposure Differences : Dentinal tubules in the coronal and middle thirds were more exposed than those in the apical third. Apical Third Observations : Decrease in tubular density and occlusion in the apical third of the root canal wall. Coronal and Middle Thirds : 500 nm and 1000 nm diamond solutions significantly differed from the EDTA group (p < 0.05). Apical Third : No significant differences between EDTA, NaOCl , H2O, and diamond solutions (p > 0.05). 500 nm and 1000 nm diamond solutions had lower smear layer removal scores across all sections compared to EDTA. Smaller Diamond Solutions ( 10 nm, 50 nm, 100 nm ) showed no significant differences from NaOCl , EDTA, and H2O groups (p > 0.05).

29. DISCUSSION Importance of irrigation in the Root Canal System Critical Role : Irrigation is essential for disinfecting, cleaning, and shaping root canals, especially in complex anatomies. Smear Layer Removal : Removing the smear layer is vital for successful treatment outcomes, as its presence can harbor bacteria and cause leakage .

30. DISCUSSION Traditional Challenges NaOCl and EDTA : Common irrigants like sodium hypochlorite ( NaOCl ) and EDTA can interfere with each other, limiting their effectiveness , especially in the apical third of the root canal. Water Block Phenomenon : Surface tension in narrow canals can prevent chelating solutions from reaching the apical third , reducing smear layer removal effectiveness.

31. DISCUSSION Innovative Approach Nanodiamonds as Irrigants : Nano-diamonds can potentially disrupt surface tension and reach all areas of the canal , improving smear layer removal. Effective Concentration : The study found that a 10 mg/mL concentration of submicron diamonds , when activated by sonic or ultrasonic oscillation , was effective in removing the smear layer across all canal sections.

32. DISCUSSION Sonic v/s Ultrasonic Irrigation Sonic Activation : More effective for smaller diamond sizes (50 nm, 100 nm) , providing better cleaning in coronal and middle thirds. Ultrasonic Activation : Better suited for larger diamond particles (500 nm, 1000 nm) but may be less effective in curved canals and with smaller particles due to energy transfer limitations .

33. DISCUSSION Material Considerations Sonic Tips : Flexible polymer tips ( EndoActivator ®) are safer and more effective in curved canals , avoiding damage to dentin walls. Ultrasonic Tips : Metal alloy tips may risk creating new smear layers and causing iatrogenic issues in curved canals.

34. S .W. O .C ANALYSIS

35. C ONCLUSION This study demonstrates that nano and submicron diamond solutions , particularly when used with sonic and ultrasonic oscillation , effectively removes the smear layer in root canals. These findings suggest nanodiamonds as a promising alternative addition to endodontic irrigants, warranting further research for clinical application.

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