Design of Laser Treatment Protocols for Bacterial Disinfection in Root Canals Using Theoretical Modeling and MicroCT Imaging

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Jennifer Gill ◽  
Dwayne Arola ◽  
Ashraf F. Fouad ◽  
Liang Zhu
Keyword(s):  
Root Canal ◽  
Thermal Damage ◽  
Elevated Temperatures ◽  
Surrounding Tissue ◽  
Tooth Root ◽  
Bioheat Equation ◽  
Human Teeth ◽  
Treatment Protocols ◽  
Theoretical Simulations ◽  
Bacterial Disinfection

Theoretical simulations of temperature elevations in root dentin are performed to evaluate, how heating protocols affect the efficacy of using erbium, chromium; yttrium, scandium, gallium, garnet (Er,Cr;YSGG) pulsed lasers for bacterial disinfection during root canal treatments. The theoretical models are generated based on microcomputer tomography (microCT) scans of extracted human teeth. Heat transfer simulations are performed using the Pennes bioheat equation to determine temperature distributions in tooth roots and surrounding tissue during 500 mW pulsed Er,Cr;YSGG laser irradiation on the root canal for eradicating bacteria. The study not only determines the heat penetration within the deep dentin but also assesses potential thermal damage to the surrounding tissues. Thermal damage is assumed to occur when the tissue is subject to a temperature above at least 47 °C for a minimum duration of 10 s. Treatment protocols are identified for three representative tooth root sizes that are capable of maintaining elevated temperatures in deep dentin necessary to eradicate bacteria, while minimizing potential for collateral thermal tissue damage at the outer root surfaces. We believe that the study not only provides realistic laser heating protocols for various tooth root geometries but also demonstrates utility of theoretical simulations for designing individualized treatments in the future.

Evaluation of Effectiveness of Er,Cr:YSGG Laser For Root Canal Disinfection: Theoretical Simulation of Temperature Elevations in Root Dentin

2009 ◽  
Vol 131 (7) ◽  
Author(s):  
L. Zhu ◽  
M. Tolba ◽  
D. Arola ◽  
M. Salloum ◽  
F. Meza
Keyword(s):  
Alternative Treatment ◽  
Root Canal ◽  
Thermal Damage ◽  
Treatment Time ◽  
Treatment Protocol ◽  
Surrounding Tissue ◽  
Bioheat Equation ◽  
Canal Surface ◽  
Theoretical Simulation ◽  
Bacterial Disinfection

Erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) lasers are currently being investigated for disinfecting the root canal system. Prior to using laser therapy, it is important to understand the temperature distribution and to assess thermal damage to the surrounding tissue. In this study, a theoretical simulation using the Pennes bioheat equation is conducted to evaluate how heat spreads from the canal surface using an Er,Cr:YSGG laser. Results of the investigation show that some of the proposed treatment protocols for killing bacteria in the deep dentin are ineffective, even for long heating durations. Based on the simulation, an alternative treatment protocol is identified that has improved effectiveness and is less likely to introduce collateral damage to the surrounding tissue. The alternative protocol uses 350 mW laser power with repeating laser tip movement to achieve bacterial disinfection in the deep dentin (800 μm lateral from the canal surface), while avoiding thermal damage to the surrounding tissue (T<47°C). The alternative treatment protocol has the potential to not only achieve bacterial disinfection of deep dentin but also shorten the treatment time, thereby minimizing potential patient discomfort during laser procedures.

Ultrasound Hyperthermia: Dose Estimation and Device Design for Intraluminal and External Delivery

2012 ◽  
Author(s):  
Danica Gordon ◽  
Chandrasekhar Thamire
Keyword(s):  
Thermal Damage ◽  
Treatment Time ◽  
The Body ◽  
Thermal Therapy ◽  
Surrounding Tissue ◽  
Temperature History ◽  
Published Data ◽  
Device Design ◽  
Treatment Protocols ◽  
Thermal Coagulation

Thermal ablation in the context of this study refers to destroying cancer cells by heating them to supraphysiological temperatures for appropriate times. Once the tumor cells and a small layer of surrounding tissue cells are killed, they are absorbed by the body over time. Compared to open surgery, radiation, and chemotherapy, thermal therapy can be less expensive and pose less risk of harmful post-procedural complications, while possessing the potential to be effective [1]. Currently microwave and radiofrequency ablation are in use for local hyperthermia; however, they lack the ability to focus heat into the target zones effectively or treat larger tumors without affecting the surrounding healthy tissue. In the current study, high frequency ultrasound (US) ablation is examined as a treatment modality because of its ability to focus and control heat effectively. Objectives of this study are to 1) develop thermal-damage correlations for US thermal therapy and 2) design delivery devices and associated treatment planning protocols. To achieve these goals, thermal damage information is first evaluated for a variety of cells and tissues from published data or pilot experiments. Required US dose levels are determined next through numerical experiments, followed by device design and estimation of thermal coagulation contours by comparing the temperature-history data against the thermal-damage data. Based on the analysis of the results for a range of parameters, namely, the applicator power, geometry, frequency, coolant parameters, treatment time, and tissue perfusion, treatment protocols are developed. Intraluminal, external, and interstitial modes of delivery are considered for focal sites in a variety of target areas. In the following sections, methods followed and sample results obtained are presented.

Evaluation of Effectiveness of Er,Cr:YSGG Laser for Root Canal Disinfection: Theoretical Simulation of Temperature Elevations in Root Dentin

2009 ◽  
Author(s):  
Liang Zhu ◽  
Mostafa Tolba ◽  
Dwayne Arola ◽  
Maher Salloum ◽  
Fernando Meza
Keyword(s):  
Root Canal ◽  
Treatment Time ◽  
Power Level ◽  
Treatment Protocol ◽  
Surrounding Tissue ◽  
Transfer Model ◽  
Bioheat Equation ◽  
Canal Surface ◽  
Theoretical Simulation ◽  
Heat Penetration

Lasers have been used in dentistry for removing hard tooth tissue for more than twenty years. Erbium, chromium: yttrium, scandium, gallium, garnet (Er, Cr: YSGG) lasers are currently being investigated for disinfecting the root canal system, since bacteria can spread from the root canal surface to the deep dentin via the dentin tubules [1]. It is expected that temperature elevation in the deep dentin is sufficient to eradicate bacteria there. Prior to using laser therapy, it is important to understand the temperature distribution and to assess thermal damage to the surrounding tissue. In this study, we develop a heat transfer model to estimate the temperature elevations in both the tooth root and surrounding tissue during Er,Cr:YSGG laser disinfection of the root canal surface. The laser power level, pulse setting, as well as laser duration are incorporated into the Pennes bioheat equation for the theoretical study. We propose a treatment protocol that achieves better heat penetration with shorter treatment time than the existing protocols used in dentistry [2].

Experimental Study of Temperature Elevations in Extracted Teeth Using a System B Heating Catheter for Bacterial Disinfection

2010 ◽  
Author(s):  
L. Zhu ◽  
M. Salloum ◽  
S. Feteih ◽  
J. Hough ◽  
D. Arola ◽  
...  
Keyword(s):  
Root Canal ◽  
Thermal Damage ◽  
Treatment Protocol ◽  
Clinical Importance ◽  
Canal Irrigation ◽  
Root Canal Irrigation ◽  
Power Setting ◽  
Root Dentin ◽  
Energy Incident ◽  
Bacterial Disinfection

Total bacterial disinfection and elimination from the human root canal system are crucial in clinical endodontic procedures [Card et al., 2002; Kakoli et al., 2009]. The current approaches relying on mechanical instrumentation and root canal irrigation and medicaments have demonstrated that eradication of bacteria occurs when the bacteria are in direct contact with the medicaments. However, persistent infection following routine treatments has suggested that bacteria may harbor in the root canal anatomical irregularities and/or deep dentinal tubules, therefore, surface irrigation of medicaments may not be able to reach those regions. Heat treatment has been used for obturation of the root canal in endodontic practice. In this study we hypothesize that as an alternative, surface heating using a System B heating catheter through the root canal surface would be effective for bacterial elimination in the deep dentin. The heat-induced cytotoxic response kills bacteria in the root dentin via heat conduction from the thermal energy incident on the root canal wall. In principle, a high power setting and/or a long heating duration can always achieve sufficient temperature elevations in deep dentin. Yet, the detailed temperature distribution inside the dentin and possible thermal damage to the supporting periodontium are unknown. Therefore, it is of clinical importance to perform and investigate temperature elevations in dentin to provide clinicians with an optimized and effective treatment protocol to minimize unnecessary thermal damage to the surrounding structure.

scholarly journals Effectiveness of a silicon-based root canal sealer for filling of simulated lateral canals

2007 ◽  
Vol 18 (1) ◽  
pp. 20-23 ◽  
Author(s):  
João Vicente Baroni Barbizam ◽  
Matheus Souza ◽  
Doglas Cecchin ◽  
Jakob Dabbel
Keyword(s):  
Root Canal ◽  
In Vitro Study ◽  
Root Canal Sealer ◽  
Human Teeth ◽  
Significance Level ◽  
Working Length ◽  
Group 3 ◽  
Group 2 ◽  
Silicon Based

The purpose of this in vitro study was to evaluate the ability of a silicon-based root canal sealer, compared to zinc oxide and eugenol and an epoxy resin-based sealers, for filling of simulated lateral canals. Thirty extracted single-rooted human teeth were selected, conventional access was made and the working length was established 1 mm from the apical foramen. Three simulated lateral canals, one in each root third (coronal, middle and apical) were prepared in both the mesial and distal surfaces of each tooth using a size 15 reamer adapted to a low-speed handpiece. Each root canal was instrumented using ProTaper rotary files up to file F3 at the working length, and then irrigated with 2.5% NaOCl followed by EDTA. The teeth were assigned to 3 groups (n=10), according to the root canal sealer: Roeko Seal (Group 1), Sealer 26 (group 2) and Grossman's sealer (Group 3). Gutta-percha cold lateral condensation technique was performed in all groups. Postoperative radiographs were taken and the images were projected for evaluation of the quality of lateral canal filling. Data were submitted to statistical analysis by Kruskal Wallis test at 5% significance level. The results showed that Grossman's sealer filled a larger number of lateral canals than Roeko Seal (p<0.05) and Sealer 26 (p<0.01). It may be concluded that Roeko Seal silicone-based root canal sealer was not as effective as the Grossman's sealer for filling of simulated lateral canals. The lateral canals localized in the apical third of the root were more difficult to be filled.

scholarly journals The effect of different irrigation techniques on the quality of cleaning of root canal walls

2008 ◽  
Vol 55 (4) ◽  
pp. 221-228
Author(s):  
Violeta Pavlovic ◽  
Slavoljub Zivkovic
Keyword(s):  
Root Canal ◽  
Smear Layer ◽  
Sodium Hypochlorite Solution ◽  
Efficient Removal ◽  
Human Teeth ◽  
Root Canals ◽  
Group I ◽  
Different Types ◽  
The Difference

Aim: To evaluate the effect of irrigation techniques, i.e. different types of irrigation needles, on the quality of cleaning of root canal walls using scanning electron microscopy (SEM). Material and Method: The study was conducted on 16 extracted, single-rooted, human teeth. The samples were allocated to two experimental groups depending on the type of the irrigation needle. Conventional needles were used for the irrigation of Group I and laterally perforated ones for Group II. All root canals were instrumented using K files and the Step-back technique. During instrumentation, all samples were irrigated with 2.5 % sodium hypochlorite solution followed by final irrigation with 17 % EDTA for 1 min. After that, all samples were irrigated with 10 ml of distilled water. The roots were, then, sectioned longitudinally and middle one third of each root canal was analyzed using SEM. Quantitative analysis was based on criteria by H?lsmann et al. Results: The obtained results showed that the more efficient removal of debris and the smear layer was accomplished in the group of samples irrigated using laterally perforated needles than conventional needles. The difference between the investigated irrigation techniques were statistically significant (p<0.01). Conclusion: The use of laterally perforated needles for irrigation allows more efficient cleaning of root canal walls, i.e. the removal of debris and the smear layer.

scholarly journals Comparative evaluation of shaping ability of trunatomy and protaper gold files in curved canals using cone?beam computed tomography: An invitro study

2021 ◽  
Vol 6 (2) ◽  
pp. 101-105
Author(s):  
Kadam Krutika Kiran ◽  
Vagarali Hemant ◽  
Pujar Madhu A ◽  
Tamase Aishwarya S ◽  
Sahana Umesh
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Root Canal ◽  
Cone Beam ◽  
Human Teeth ◽  
Root Canals ◽  
Before And After ◽  
Canal Transportation ◽  
Group 2 ◽  
Shaping Ability

This study aimed to compare the canal transportation and canal centering ability in the preparation of curved root canals after instrumentation with TruNatomy (TN) (TN; Dentsply Sirona, Maillefer, Ballaigues, Switzerland) and ProTaper Gold (PG) (PG; Dentsply, Tulsa Dental Specialties, Tulsa, OK, USA) files using cone‑beam computed tomography (CBCT). 30 Single rooted extracted human teeth with root curvature ranging from 20-30° according to Schneider’s method were selected. Teeth with any visible cracks or fractures, calcifications, previous root canal treatments were excluded. The teeth were randomly assigned into two groups i.e. Group 1-TN and Group 2-PG (n = 15 each). The teeth were instrumented according to manufacturer’s guidelines for both the groups. Canals were scanned using a CBCT scanner before and after preparation to evaluate the transportation and centering ratio at 3 mm, 5 mm, and 7 mm from the apex. The data analysis was done using SPSS software and the test used was independent sample t test for comparison between the 2 groups.Data obtained suggested that TN group presented lesser canal transportation at the middle third of the root. The PG group showed better centering abitily at apical third of the root canal when both the groups were compared. TN resulted in less transportation than PG at the middle third, and PG showed better centering ability at the apical third. Overall, both systems safely prepared root canals, causing minimal errors.

scholarly journals Implantation and Retrieval of Magnetic Nanobots for Treatment of Endodontic Re-Infection in Human Dentine

2021 ◽  
Author(s):  
Debayan Dasgupta ◽  
Shanmukh Srinivas Peddi ◽  
Deepak K. Saini ◽  
Ambarish Ghosh
Keyword(s):  
Root Canal ◽  
Treatment Method ◽  
Therapeutic Modality ◽  
Clinical Practices ◽  
Human Teeth ◽  
Dentinal Tubules ◽  
Current State ◽  
Human Dentine ◽  
New Treatment ◽  
Magnetic Drive

<div> <div> <div> <p>More than 10% of root canal treatments undergo failure worldwide due to remnant bacteria deep in the dentinal tubules located within the dentine tissue of human teeth. Owing to the complex and narrow geometry of the tubules, current techniques relying on passive diffusion of anti-bacterial agents are inadequate. Here, we present a new treatment method using actively maneuvered nanobots, which can be incorporated during standard root canal procedure. Our technique will enable dentists to execute procedures inside the dentine not yet possible by current state of the art. We demonstrate that magnetically driven nanobots can reach the depths of the tubules up to hundred times faster than current clinical practices. Subtle modifications of the magnetic drive allowed deep implantation of the nanobots isotopically distributed throughout the dentine, along with spatially controlled retrieval from selected areas. Finally, we demonstrate the integration of bactericidal therapeutic modality with the nanobots, thereby validating the tremendous potential of nanobots in dentistry, and nanomedicine in general. </p> </div> </div> </div>

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