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.

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].

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.

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.

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.

scholarly journals Analysis of the Morpho-Geometrical Changes of the Root Canal System Produced by TF Adaptive vs. BioRace: A Micro-Computed Tomography Study

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 531
Author(s):  
Loai Alsofi ◽  
Muhannad Al Harbi ◽  
Martin Stauber ◽  
Khaled Balto
Keyword(s):  
Surface Area ◽  
Root Canal ◽  
Type I ◽  
Structure Model ◽  
Canal Surface ◽  
Canal System ◽  
Structure Model Index ◽  
Continuous Rotation ◽  
Before And After ◽  
Root Canal System

We aimed to analyze the morpho-geometric changes of the root canal system created by two rotary systems (TF Adaptive and BioRace) using micro-CT technology. Two concepts of rotary file system kinematics, continuous rotation and adaptive kinematics, were used in root canal preparation. Twenty mandibular molars (n = 20) were selected with the following criteria: the teeth have mesial roots with a single and continuous isthmus connecting the mesiobuccal and mesiolingual canals (Vertucci’s Type I configuration) and distal roots with independent canals. Teeth were scanned at a resolution of 14 μm. Canals were divided equally into two groups and then enlarged sequentially using the BioRace system and TF Adaptive system according to manufacturer protocol. Co-registered images, before and after preparation, were evaluated for morphometric measurements of canal surface area, volume, structure model index, thickness, straightening, and un-instrumented surface area. Before and after preparation, data were statistically analyzed using a paired sample t-test. After preparation, data were analyzed using an unpaired sample test. The preparation by both systems significantly changed canal surface area, volume, structure model index, and thickness in both systems. There were no significant differences between instrument types with respect to these parameters (p > 0.05). TF Adaptive was associated with less straightening (8% compared with 17% for BioRace in the mesial canal, p > 0.05). Both instrumentation systems produced canal preparations with adequate geometrical changes. BioRace straightened the mesial canals more than TF Adaptive.

Root canal surface after application of an x-ray opaque waveguide

2004 ◽  
Author(s):  
Tatjana Dostalova ◽  
Helena Jelinkova ◽  
Marie Bartonova ◽  
Jan Sulc ◽  
Michal Nemec ◽  
...  
Keyword(s):  
Root Canal ◽  
Canal Surface ◽  
X Ray

CASE REPORT: THE EMERGENCE OF ANTICOCCIDIAL-RESISTANT STRAINS OF Eimeria IN TAIWAN

2020 ◽  
Vol 46 (01) ◽  
pp. 45-48 ◽  
Author(s):  
Meng-Ting Hsieh ◽  
Jyh-Mirn Lai ◽  
Yao-Chi Su ◽  
Wei-Che Kung ◽  
Cheng-Hsun Lee ◽  
...  
Keyword(s):  
Case Report ◽  
Alternative Treatment ◽  
Treatment Protocol ◽  
Dairy Goats ◽  
Eimeria Spp ◽  
Resistant Strains

Although anticoccidial-resistant Eimeria spp. have been reported in avian industry, it has yet to be officially identified in dairy goats in Taiwan. This paper describes Eimeria strains, identified from a five-week-old kid, found to be resistant to sulfonamide drugs, due to the fact that the number of oocysts per gram of feces (O.P.G.) remained to be 9200 after seven consecutive days of treatment and only dropped to zero after another two consecutive days of treatment with toltrazuril. We believe this is the first paper to identify the emergence of an anticoccidial-resistant Eimeria spp. strain, and further investigation should be warranted. This paper would help farmers and veterinarians consider an alternative treatment protocol when dealing with coccidiosis in the goat industry.

scholarly journals Predictive validity of the Brazilian version of the Expected Treatment Outcome Scale in cocaine-dependent outpatients at a drug treatment referral center

2005 ◽  
Vol 27 (3) ◽  
pp. 225-227
Author(s):  
Marcelle Maria Lobo Dinis ◽  
Sonia Regina Lambert Passos ◽  
Luiz Antonio Bastos Camacho
Keyword(s):  
Treatment Outcome ◽  
Predictive Value ◽  
Treatment Time ◽  
Medication Compliance ◽  
Treatment Protocol ◽  
Area Under The Curve ◽  
Third Party ◽  
Double Blind ◽  
Brazilian Version ◽  
Scale Scores

BACKGROUND: High dropout rates among patients under treatment for cocaine dependence have stimulated research into predictors of treatment outcome. OBJECTIVE: To assess the predictive value of the Brazilian version of the Expected Treatment Outcome Scale. METHODS: The original English version of the scale was translated and back-translated. A total of 210 subjects participating in a 10-week randomized double-blind clinical trial (nefazodone versus placebo) completed the questionnaire at their first appointment. Mean Expected Treatment Outcome Scale scores were compared with treatment outcomes. RESULTS: There were ten subjects (5%) who failed to complete at least six items, and 37 (17.5%) failed to complete 1 to 3 items. The most frequently unanswered questions involved time estimates (treatment time and abstinence) and third-party judgments. The mean score was 34.4 (9.3) (median, 33.9). There were no differences in mean scores between subjects evaluated in the first to the fifth appointment 35.2 (9.3) or in the sixth to the eleventh appointment 35.2 (9.3) (p = 0.13); completing the treatment 33.8 (10.3) or not 34.6 (9.1) (p = 0.64); remaining abstinent for three weeks 34 (9.3) or not 34.8 (9.4) (p = 0.58), and medication compliance 33.9 (8.8) or noncompliance 35.3 (10.3) (p = 0.34). The ROC curve of Expected Treatment Outcome Scale scores, when dropout was defined as not appearing for all 11 appointments, was linear, with an area under the curve of .54 (range, .44-.64), suggesting that the scale is ineffective in discriminating between cases and noncases. CONCLUSION: In this study, the Brazilian version of the Expected Treatment Outcome Scale was found to have no predictive value for treatment adherence and abstinence in cocaine-dependent subjects subjected to a standardized treatment protocol.

scholarly journals Definitive radiotherapy consisting of whole pelvic radiotherapy with no central shielding and CT-based intracavitary brachytherapy for cervical cancer: feasibility, toxicity, and oncologic outcomes in Japanese patients

2020 ◽  
Vol 25 (11) ◽  
pp. 1977-1984
Author(s):  
Takeaki Kusada ◽  
Takafumi Toita ◽  
Takuro Ariga ◽  
Wataru Kudaka ◽  
Hitoshi Maemoto ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Treatment Time ◽  
Treatment Protocol ◽  
Japanese Patients ◽  
Oncologic Outcomes ◽  
Intracavitary Brachytherapy ◽  
High Dose ◽  
Tumor Diameter ◽  
Pelvic Radiotherapy ◽  
Definitive Radiotherapy

Abstract Background This prospective study investigated the feasibility, toxicity, and oncologic outcomes of definitive radiotherapy (RT) consisting of whole pelvic radiotherapy with no central shielding (noCS-WPRT) and CT-based intracavitary brachytherapy (ICBT) in Japanese patients with cervical cancer. Methods Patients with cervical cancer of FIGO stages IB1–IVA were eligible. The treatment protocol consisted of noCS-WPRT of 45 Gy in 25 fractions and CT-based high dose-rate ICBT of 15 or 20 Gy in 3 or 4 fractions prescribed at point A. The prescribed ICBT dose was decreased if the manual dwell time/position optimization failed to meet organs-at-risk constraints. Graphical optimization and additional interstitial needles were not applied. Results We enrolled 40 patients. FIGO stages were IB1: 11, IB2: 13, IIA2: 1, IIB: 11, IIIB: 3, and IVA: 1. Median (range) pretreatment tumor diameter was 47 (14–81) mm. Point A doses were decreased in 19 of 153 ICBT sessions (12%). The median follow-up duration was 33 months. The 2-year rates of pelvic control, local control (LC), and progression-free survival were 83%, 85%, and 75%, respectively. Pre-ICBT tumor diameter, high-risk clinical target volume (HR-CTV), total HR-CTV D90, and overall treatment time (OTT) significantly affected LC. Late adverse events (grade ≥ 3) were observed in 3 patients (2 in the bladder, 1 in the rectum). Conclusions Definitive RT consisting of noCS-WPRT and CT-based ICBT was feasible for Japanese patients with cervical cancer. To further improve LC, additional interstitial needles for patients with a large HR-CTV and shorter OTT should be considered.

Thermal Therapy Protocols for Benign Prostatic Hyperplasia

2007 ◽  
Author(s):  
Daniel Chinn ◽  
Elvis Nditafon ◽  
Alvin Yew ◽  
Chandrasekhar Thamire
Keyword(s):  
Benign Prostatic Hyperplasia ◽  
Thermal Damage ◽  
Prostatic Hyperplasia ◽  
Operating Conditions ◽  
Thermal Therapy ◽  
Bioheat Transfer ◽  
Surrounding Tissue ◽  
Accurate Estimation ◽  
Transfer Model ◽  
Porous Media Model

Thermal therapy for treatment of benign prostatic hyperplasia (BPH) is becoming increasingly popular due to the minimally invasive nature of the treatment. Successful management of such therapy requires accurate estimation of thermal dosage. The purpose of this study is to provide correlations for the thermal damage caused by ultrasound, microwave, and infrared devices under a range of operating conditions. A boundary-fitting finite difference method is used to examine the heat transfer in the prostate gland and surrounding tissue. The Pennes bioheat transfer model and a porous media model were utilized to calculate temperature histories. Necrosis zones were determined using published necrosis data for prostatic tissue and cells. Thermal damage correlations for the three different hyperthermia sources along with sample temperature contours and necrosis zones are presented. Results indicate that the applicator power level and heating time are the most important parameters in achieving the desired necrosis zones, while coolant parameters strongly affect the temperatures of the sensitive urethra and serve as constraints for protocol parameters. Out of the three sources evaluated, ultrasound modality appears to be the most capable of causing necrosis in the target zones, with least damage to the surrounding healthy tissues.

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