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1.
J Contemp Dent Pract ; 21(1): 1, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32381792

RESUMO

Root canal treatment is one of the most challenging practices in dentistry as the complexity and the variability of the endodontic space can often lead the operator to create false trajectories or missing canals. The technical advances in the development of even more efficient and resistant endodontic instrument reached important results in the last few years with the adoption of NiTi alloys and thermal treatments, which could increase the flexibility and the resistance of the instruments.1,2.


Assuntos
Endodontia , Ligas , Ligas Dentárias , Assistência Odontológica , Humanos , Tratamento do Canal Radicular
2.
J Contemp Dent Pract ; 21(2): 113, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32381811

RESUMO

The role of nickel-titanium (NiTi) in the production of endodontic instruments increased in the last few decades; therefore, the way of evaluation of its performance increased as well. Nowadays, there are several ways to evaluate NiTi instruments, divided into static and dynamic tests. The static ones are cyclic fatigue tests, torsional resistance tests, flexibility, and cutting efficiency tests. These methodologies have been deeply used to evaluate some of the metallurgical properties of the instruments on the market. Up-to-date, we know very well the behavior of NiTi under static conditions, but these knowledges are too fragmented to be relevant for understanding and evaluating the complexities of intracanal instrumentation. Starting from the purpose to introduce the variable of movement in the testing procedure, some dynamic tests have been proposed, such as dynamic cyclic fatigue test.1,2 Although these kinds of studies were capable of evaluating more precisely the behavior of rotary instruments inside the root canal, they could not take into account, at this moment, the complexities of stresses that instruments undergo during the shaping procedure.3-5 Therefore, some of these tests are not accepted anymore by the scientific community and on the contrary they do not help the general practitioner to orientate in the large amount of rotary instruments present on the market.6 This tends to withdraw the general dentistry from the scientific literature, wearing a groove between the practice and the science.7 Starting from these ideas, in the last couple of years some authors started to think the proper way to real-time evaluation of the performance of NiTi rotary instruments inside the root canal. To do so, a countable and repeatable measurement of instrument's developed stresses was needed. Setzer and Böhme8 first used the torque generated by Revo-S, Vortex, and ProFile to evaluate their performance during instrumentation. The so-called "operative torque" is the summation of torque generated in each point of the instrument during its simultaneous movement around its own axis and up and down inside the canal. The recorded values are influenced by both torsional and flexural stresses, becoming this way a reliable method to analyze, evaluate, and compare the performance of NiTi instruments inside the root canal.9 This methodology is applicable for not only in vitro but also in vivo measurement, as demonstrated by Gambarini et al.10 The main drawback of this kind of evaluation is the not well-determined correlation between the torsional and the flexural stresses; therefore, it is still unpredictable how each influence the other. In conclusion, the potential of real-time torque measurement is wide and still unexplored, but further studies are needed to better understand how torque is developed inside the root canal.


Assuntos
Níquel , Titânio , Ligas Dentárias , Preparo de Canal Radicular , Torque
3.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 38(2): 160-165, 2020 Apr 01.
Artigo em Chinês | MEDLINE | ID: mdl-32314889

RESUMO

OBJECTIVE: This study aims to compare the efficiency of three kinds of microtube extraction devices, namely, instrument removal system (IRS), micro-retrieve and repair (MR&R) system, and MR&R system using modified microtube in removing separated instruments with different exposure lengths. METHODS: After a cross-section platform model was established, the IRS, MR&R, and MR&R modified microtube system with sidewall window reduced to 0.20 mm were used to retrieve various separated instrument models, and the differences in extraction effects were statistically analyzed by Chi-square test. The separated instrument models were divided into two groups: stainless steel and nickel-titanium instrument groups. In total, 23 instruments were tested for three times each. RESULTS: When the exposed length of separated instrument was 0.50 mm, the removal efficiency of the modified MR&R system group was significantly higher than those of the IRS and MR&R system groups (P<0.001). When the broken end of the fracture instrument was up to 1.00 mm, the success rates of the MR&R system and modified MR&R groups were significantly higher than that of the IRS group (P<0.01). No difference was observed among these three devices when the exposure length of separated instruments was 1.50 mm or higher. CONCLUSIONS: The MR&R and modified MR&R systems have good removal effect when the exposed length of separated instrument is small.


Assuntos
Instrumentos Odontológicos , Preparo de Canal Radicular , Ligas Dentárias , Cavidade Pulpar , Desenho de Equipamento , Falha de Equipamento , Aço Inoxidável , Titânio
4.
Am J Orthod Dentofacial Orthop ; 157(3): 320-328, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32115110

RESUMO

INTRODUCTION: This study compared three-dimensional forces delivered to the displaced tooth and its adjacent teeth between passive self-ligation (PSL) and conventional elastic ligation (CL) in simulation of mandibular lateral incisor linguoversions. METHODS: A multisensor system was used to measure three-dimensional forces delivered to brackets attached to the mandibular left central incisor, lateral incisor, and canine (FDI tooth numbers 31, 32, and 33, respectively). Two ligation methods (PSL and CL), 3 nickel-titanium (0.014-inch) archwires similar to the arch form of normal occlusion, and 2 displacements (1 and 4 mm) were tested. RESULTS: In 1-mm displacement, forces were significantly smaller in CL than in PSL at 32 in the labial direction and larger at 31 in the mesial direction for all 3 types of archwires (P <0.01 for both). For 2 of 3 archwires, forces were larger in CL than in PSL at 33 in the lingual direction (P <0.01). In 4-mm displacement, forces were significantly larger in CL than in PSL at 31 in the mesial direction and significantly smaller in CL than in PSL at 33 in the distal direction for all 3 archwires (P <0.05 and P <0.01, respectively). Mean forces in the vertical direction were small, ranging from -0.05 to 0.05 N. CONCLUSIONS: Under a small amount of displacement, force magnitude in PSL was smaller than that in CL at the displaced tooth in labial-lingual directions. Under a large amount of displacement, a more "open coil spring effect" was significantly obtained in CL than PSL at both adjacent teeth of the displaced tooth.


Assuntos
Incisivo , Braquetes Ortodônticos , Técnicas de Movimentação Dentária , Ligas Dentárias , Análise do Estresse Dentário , Humanos , Desenho de Aparelho Ortodôntico , Fios Ortodônticos , Titânio
5.
Dental Press J Orthod ; 25(1): 64-69, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32215479

RESUMO

OBJECTIVE: This study proposed to investigate the influence of catastrophizing and others factors related to pain during orthodontic treatment. METHODS: 27 patients with 0.022 x 0.028-in Straight-wire brackets were evaluated during alignment and leveling phase with nickel-titanium wires. Visual Analog Scales measured the intensity of orthodontic pain at six moments after a clinical appointment: 6 first hours; 1, 2, 3, 5, and 7 days. Multiple linear regression and stepwise approach assessed the influence of the following variables on pain: catastrophizing, sex, age, duration of treatment, clinical appointment time (morning or afternoon), and wire diameter. RESULTS: The highest pain intensity was reported 24 hours after activation. These data were used to analyze factors associated with pain level. Age (r = 0.062, p= 0.7586), sex (p= 0.28), catastrophizing (r = -0.268, p= 0.1765), and orthodontic wire diameter (r = 0.0245, p= 0.2181) were not correlated with orthodontic pain in the univariate statistics. Catastrophizing was included in the multiple regression model because it was of great interest. Duration of orthodontic treatment (r = 0.6045, p= 0.0008) and the time when orthodontic appliance was activated (p= 0.0106) showed statistical significant associations with pain, and were also included in the multivariate regression, which showed that about 32% of orthodontic pain could be explained by the duration of treatment (R2= 0.32, p= 0.0475). Catastrophizing (R2= 0.0006, p= 0.8881) and clinical appointment time were not significantly associated with pain (R2= 0.037, p= 0.2710). CONCLUSIONS: Pain after activation of fixed orthodontic appliance is not associated with catastrophizing as well as age, sex, orthodontic wire diameter, and period of activation.


Assuntos
Braquetes Ortodônticos , Catastrofização , Ligas Dentárias , Humanos , Desenho de Aparelho Ortodôntico , Fios Ortodônticos , Dor , Titânio
6.
J Endod ; 46(3): 391-396, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32029265

RESUMO

INTRODUCTION: Information is scarce regarding current usage practices of nickel-titanium (NiTi) engine-driven instruments in clinical practice. Therefore, the specific purpose of this survey was to assess trends among endodontists regarding the use and reuse of NiTi instruments. METHODS: A 16-question survey was sent by e-mail to about 4000 active members of the American Association of Endodontists. Data were collected over a 6-month period and compared using chi-square tests. RESULTS: A total of 957 surveys were collected (response rate = 23%). Of the respondents, 40.2% worked in solo practices; among them, there were significantly fewer recent graduates (<10 years) compared with those who graduated more than 10 years ago. Furthermore, 41.7% were in a group practice, 4.3% in corporate practice, 10.7% in university settings, and 3% in the military. Overall, 98.3% of respondents reported using NiTi instruments. Respondents who graduated less than 25 years ago use NiTi instruments significantly more (99%) than those who graduated more than 25 years ago (92.6%). Although 22.9% of respondents buy presterilized instruments, 41.6% sterilize them before use, and 35.5% do not sterilize new instruments before use; dental officers in the military reported that they use sterile new instruments in 100% of cases. NiTi instruments were reused by 74% of respondents. The 2 largest segments of the specialist endodontic instrument market belonged to Dentsply (York, PA; 56.9%) and EdgeEndo (Albuquerque, NM; 28.8%). CONCLUSIONS: There are significant differences in the use of NiTi instruments among types of practice and years since graduation. There were noticeable changes compared with findings reported about 10 years ago.


Assuntos
Ligas Dentárias , Instrumentos Odontológicos , Endodontistas , Desenho de Equipamento , Humanos , Níquel , Padrões de Prática Odontológica , Preparo de Canal Radicular , Inquéritos e Questionários , Titânio , Estados Unidos
7.
J Endod ; 46(3): 431-436, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31911005

RESUMO

INTRODUCTION: The aim of this study was to compare the influences from different access angles and curvature radii on cyclic fatigue resistance of nickel-titanium rotary files. METHODS: Two file systems (2Shape [TS; MicroMega, Besançon, France] and HyFlex CM [HCM; Coltène/Whaledent, Allstätten, Switzerland]) were used. A total of 192 instruments of TS #25/.04 (TS1), TS #25/.06 (TS2), HCM #25/.04, and HCM #25/.06 were evaluated at 3 insertion angles (0°, 10°, and 20°) and 2 radii (5 mm and 3 mm) in 16-mm stainless steel artificial canals with a 60° curvature. Cyclic fatigue resistance was determined by the number of cycles to failure (NCF) using a customized testing device. Data were analyzed statistically with the significance level established at 95%. RESULTS: In the 3-mm radius canal, the instruments showed lower cyclic fatigue resistance than in the 5-mm radius canal (P < .05). HCM #25/.06 and all .04 taper instruments had a significant NCF reduction at 20° and 10° in the 3-mm radius canal (P < .05), whereas TS2 showed no significant differences. In the 5-mm radius of curvature, although .06 taper instruments had no significant NCF reduction for each angle tested, .04 taper files exhibited significant NCF reduction when tested at 20° (P < .05). Comparing the same size instruments, HCM had higher NCF than TS (P < .05). Instruments with a .04 taper exhibited higher NCF than the .06 ones with the same heat treatment (P < .05). CONCLUSIONS: An inclined insertion into the canals decreased cyclic fatigue resistance of thermal-treated instruments with a .04 taper at all radii of curvature tested. The synergistic effect of a small radius of curvature and access angulation of heat-treated instruments decreases their fatigue resistance.


Assuntos
Ligas Dentárias , Instrumentos Odontológicos , Falha de Equipamento , Níquel , Titânio , Cavidade Pulpar , Desenho de Equipamento , Teste de Materiais , Rádio (Anatomia) , Preparo de Canal Radicular
8.
Dent Mater ; 36(3): 431-441, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31992484

RESUMO

OBJECTIVE: The Ti-6Al-4V (TAV) alloy is commercially used as a dental implant material. This work seeks to elucidates the origins of degradation of Ti-6Al-4V (TAV) implant alloys that result in peri-implant bone loss. 
Methods: In this work, a combination of microstructure, surface, and solution analyses was utilized to study the corrosion mechanism of the TAV alloy in oral environments. The corrosion of TAV alloys in the F--enriched environment of a crevice was evaluated through nanoscale surface analysis. And, the findings were further rationalized via electrochemical means. 
 RESULTS: Our results suggest the bone loss was caused by crevice corrosion and the consequential release of by-products, and the crevice corrosion was potentially induced by the buildup of corrosive species such as fluorides, which are common additives in dental products. In turn, the corrosion properties of the TAV alloy were evaluated in fluoride enriched environments. Nanoscale analysis of corroded surfaces, carried out using vertical scanning interferometry (VSI) showed that the corrosion susceptibility of the constituent phases dictates the corrosion product species. In specific, the aluminum-rich α phase preferentially dissolves under potential-free conditions and promotes the formation of insoluble Al-Ti oxides. Notably, under conditions of applied potential, oxidative dissolution of the vanadium-rich ß phase is favored, and the vanadium release is promoted. 
 SIGNIFICANCE: These findings elucidate the origins of degradation of TAV-implants that result in the release of corrosion by-products into the local biological environment. More important, they offer guidelines for materials design and improvement to prevent this nature of degradation of dental implants.


Assuntos
Implantes Dentários , Ligas , Corrosão , Ligas Dentárias , Teste de Materiais , Saliva Artificial , Propriedades de Superfície , Titânio
9.
Niger J Clin Pract ; 23(1): 41-45, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31929205

RESUMO

Objective: This in vitro study aimed to compare the cyclic fatigue resistance of HyFlex EDM (HEDM), Vortex Blue (VB), ProTaper Gold (PG), and OneCurve (OC) nickel-titanium (NiTi) instruments. Materials and Methods: About 12 HEDM (25/.~), 12 VB (25/.06), 12 PG (25/.08), and 12°C (25/.06) instruments were included in this study. All the instruments were tested with a 60° angle of curvature and a 3-mm radius of curvature. All the instruments were utilized until fracture occurred, and then the number of cycles to failure (NCF) was calculated. The data were analyzed statistically using Kruskal-Wallis H and Mann-Whitney U-tests. The statistical significance level was set at P < 0.05. Results: HEDM instruments had the highest cyclic fatigue resistance among all the other instruments (P < 0.05). The OC instruments had a significantly higher fatigue resistance than the PG and VB instruments (P < 0.05); however, there was no significant difference between PG and VB instruments in the NCF (P > 0.05). Conclusion: Within the limitations of this in vitro study, it was found that the cyclic fatigue resistance was higher for the HEDM instruments than for the VB, PG, and OC instruments.


Assuntos
Ligas Dentárias/química , Instrumentos Odontológicos , Falha de Equipamento , Teste de Materiais , Preparo de Canal Radicular/instrumentação , Ligas , Desenho de Equipamento , Ouro , Humanos , Níquel/química , Titânio/química
10.
J Endod ; 46(2): 232-237, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31889584

RESUMO

INTRODUCTION: Optimum torque reverse (OTR) motion is a torque-sensitive reciprocal motion in which the motor rotates in alternating 90° counterclockwise and 180° clockwise rotation when the torque exceeds a predetermined value. This study aimed to examine whether OTR motion contributes to torque and force reduction during nickel-titanium rotary instrumentation with the crown-down or single-length technique. METHODS: Twenty-eight simulated straight canals in resin blocks were divided into 2 groups according to the type of motion (OTR or continuous rotation). The groups were further subdivided according to the preparation technique (crown-down or single-length technique, n = 7 each). Automated root canal instrumentation was performed with a torque/force analyzing device (300 rpm, up-and-down speed of 10 mm/min) and EndoWave instruments (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) to size #25/0.06 taper. Maximum torque and apical force were recorded and analyzed with analysis of variance and the Bonferroni test. RESULTS: During the crown-down preparation phase (#35/0.08, #30/0.06, #25/0.06, and #20/0.06), OTR motion developed lower maximum torque and upward force (representing the screw-in force) than continuous rotation. During the apical preparation phase (#25/0.06), OTR motion generated significantly lower maximum clockwise and counterclockwise torque (P < .05) when the single-length technique was used and significantly lower maximum upward force regardless of the preparation technique (P < .05) compared with continuous rotation. CONCLUSIONS: Under the present experimental conditions, OTR motion reduced both torque and screw-in force during the crown-down preparation phase of the crown-down technique and during the apical preparation phase of the single-length technique.


Assuntos
Cavidade Pulpar , Preparo de Canal Radicular , Coroas , Ligas Dentárias , Desenho de Equipamento , Rotação , Titânio , Torque
11.
Dent Mater J ; 39(1): 9-11, 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-31511476

RESUMO

The demand for titanium and titanium alloys in dentistry is high. A surveillance survey regarding the clinical and laboratory uses of titanium/titanium alloys in Japan was conducted in this study. The alloys used for casting demonstrated a decreasing tendency in quantity, whereas the use of non-casting titanium alloys increase in the market. This increasing trend is reflected the popularity of CAD/CAM devices. In Japan, the processing technologies of titanium alloys have been improved; therefore, the application of titanium and titanium alloys to dental procedures covered by the insurance is clearly worth considering.


Assuntos
Ligas , Titânio , Ligas de Cromo , Ligas Dentárias , Técnica de Fundição Odontológica , Japão
12.
Clin Oral Investig ; 24(1): 351-355, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31102046

RESUMO

OBJECTIVES: The aim of the present study was to determine the effect of taper (.08, .06, and .04) of separated K3XF instruments on duration taken for the secondary fracture formation during ultrasonic activation. MATERIALS AND METHODS: Ten 25/.08 K3XF (SybronEndo, Orange, CA, USA), ten 25/.06 K3XF, and ten 25/.04 K3XF instruments were used for the study. The apical 5 mm of the instruments was cut to simulate the fragments in root canals. Fragments of the instruments were sandwiched between two straight dentin blocks. An ultrasonic tip was used to cause a secondary fracture of the fragment. The time needed for the secondary fracture was recorded for each instrument. The data were statistically analyzed using the Kruskal-Wallis H test (alpha = 0.05). RESULTS: Secondary fractures occurred in all instruments. In the .08 taper group, secondary fractures took longer than in the case of the .06 and the .04 taper groups (P < 0.05). There were no significant differences between the .06 and the .04 taper groups in terms of the time required for the occurrence of a secondary fracture (P > 0.05). CONCLUSIONS: In the .08 taper group, secondary fracture took longer time than in the case of the .06 and the .04 taper groups due to its larger cross-sectional area involved. CLINICAL RELEVANCE: Typically, when removing separated instruments, a much lower power setting is chosen. The purpose of this in vitro study was to determine which tapered files were more resilient to secondary fracture, thus allowing a higher power setting to be chosen. Thus, the results of the present study cannot be used in clinical practice. If the clinician knows the taper of the broken file, the clinician should be very careful with regard to secondary fractures when using ultrasonics to remove the separated smaller tapered instruments.


Assuntos
Cavidade Pulpar , Preparo de Canal Radicular , Ultrassom , Ligas Dentárias , Instrumentos Odontológicos , Desenho de Equipamento , Níquel , Titânio
13.
J Endod ; 46(1): 110-115, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31740067

RESUMO

INTRODUCTION: The aim of this study was to compare a reduction in working length and area of canal enlargement resulting from instrumentation with Hedström (Kerr Dental, Orange, CA), K (Kerr Dental), ProTaper Next (Dentsply Sirona, York, PA), and TF Adaptive (Kerr Dental) files. The effect of the canal curvature on the working length and area of canal enlargement was also assessed. METHODS: A total of 80 plastic canal models were used, 40 with a canal curvature of 10° and another 40 with a canal curvature of 30°. Instrumentation of 10 models with a 10° canal curvature and 10 models with a 30° canal curvature was performed using each of the file systems up to size 25. Working length measurements were taken before and after instrumentation with each file type and size. Twenty composite images were made from superimposition of pre- and postpreparation photographs, and the difference in area was calculated using ImageJ software (National Institutes of Health, Bethesda, MD). RESULTS: ProTaper Next rotary files and TF Adaptive files produced the smallest reduction in the working length and the least canal enlargement followed by Hedström files and K files, respectively. The degree of canal curvature increased the working length reduction by a significant amount when K files and ProTaper Next rotary files were used, and the degree of curvature increased canal enlargement by a significant amount when K files were used. CONCLUSIONS: Nickel-titanium rotary files produced more favorable results than stainless steel hand files in terms of maintaining a consistent working length and producing minimal canal enlargement. Hedström files performed significantly better than K files in terms of working length reduction and canal enlargement.


Assuntos
Cavidade Pulpar , Preparo de Canal Radicular , Ligas Dentárias , Instrumentos Odontológicos , Desenho de Equipamento , Preparo de Canal Radicular/instrumentação , Titânio
14.
Gen Dent ; 68(1): 36-39, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31859660

RESUMO

The aim of this study was to compare, in pairs, the cyclic fatigue resistance, scanning electron microscopic (SEM) appearance, and energy-dispersive X-ray (EDX) profiles of 6 rotary files: ProTaper Gold vs EdgeTaper Platinum; ProTaper Universal vs EdgeTaper; and Vortex Blue vs EdgeSequel Sapphire. Six types of rotary file were tested in 2 sizes of each type. A 3-point cyclic fatigue apparatus imparting a 60-degree angle of curvature and a 3-mm radius of curvature was used to evaluate 30 files of each type and size. The cyclic fatigue testing results from similar file types and sizes were paired for statistical analysis. After fatigue testing was completed, 36 files (3 of each type and size) were randomly selected for SEM imaging and EDX analysis. When similar file types and sizes were paired in independent-samples t tests, statistically significant differences (P < 0.0001) in cyclic fatigue resistance were established. For both tested sizes, EdgeTaper Platinum exhibited significantly greater fatigue resistance than ProTaper Gold. ProTaper Universal and EdgeTaper each demonstrated significantly greater fatigue resistance than the other system in 1 size pairing. Vortex Blue exhibited significantly greater fatigue resistance than EdgeSequel Sapphire in both size pairings. In general, the heat-treated files demonstrated greater cyclic fatigue resistance than the non-heat-treated files. The SEM images verified that fracture patterns were consistent with cyclic fatigue failure. Differences in file design between the matched pairs were noted, particularly at the tips. The EDX comparisons showed that nickel and titanium were present in similar percentages (1:1 atomic ratio) for all file types. The disparities in cyclic fatigue results and tip design indicate that clinicians should not expect identical clinical performance from different files.


Assuntos
Instrumentos Odontológicos , Falha de Equipamento , Microscopia Eletrônica de Varredura/métodos , Preparo de Canal Radicular , Ligas Dentárias , Desenho de Equipamento , Humanos , Teste de Materiais , Níquel , Estresse Mecânico , Titânio
15.
J Contemp Dent Pract ; 20(8): 935-939, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31797850

RESUMO

AIM: To evaluate and compare in vitro the dentinal crack formation in root canal dentin after root canal instrumentation with hand K-Flex files, ProTaper Next, and self-adjusting engine-driven files. MATERIALS AND METHODS: Ninety-two human mandibular first molar teeth were randomly divided into four groups (n = 23) as per the instrumentation protocol: group I-unprepared teeth (control); group II-hand K-Flex files (Sybron Endo); group III-ProTaper Next X1 and X2 (Dentsply Maillefer); group IV-self-adjusting file (ReDent Nova, Israel). All the roots were sectioned perpendicular to the long axis of the tooth at 9 mm, 6 mm, and 3 mm from the apex and thereby obtaining sixty-nine samples, which were then subjected to a stereomicroscopic examination for detection of dentinal cracks. Statistical analyses were done using the Chi-square test with SPSS (version 19), and p value was set at p < 0.05. RESULTS: Statistically significant differences were seen between the instrumented groups. No dentinal cracks were found in the unprepared roots and those prepared with hand K-Flex files (0/23). Self-adjusting-file-instrumented group showed significantly less incidence of crack formation when compared to the ProTaper Next group with p = 0.001. CONCLUSION: Self-adjusting file is an efficient engine-driven NiTi instrument for root canal instrumentation with the least occurrence of crack formation in the root canal dentin compared to the ProTaper Next system. CLINICAL SIGNIFICANCE: The introduction of NiTi rotary file systems has metamorphosed the endodontic treatment by their better cutting efficiency and cleaning potentiality. Yet, evidenced-based clinical studies are to be conducted on the incidence of microfractures that can lead to vertical root fractures, which will be produced irrespective of the motion kinematics and design feature and thereby compromising the clinical maintenance of the endodontically treated teeth.


Assuntos
Cavidade Pulpar , Preparo de Canal Radicular , Ligas Dentárias , Ego , Mãos , Humanos
16.
Prog Orthod ; 20(1): 46, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31840204

RESUMO

BACKGROUND: To compare the clinical efficiency of premium heat-activated copper nickel-titanium (Tanzo Cu-NiTi) and NT3 superelastic NiTi during initial orthodontic alignment. SUBJECT AND METHODS: A total of 50 patients were randomly allocated to 1 of 2 different archwire types (group 1, Tanzo Cu-NiTi; group 2, NT3 superelastic NiTi). Eligibility criteria included Class I or Class II malocclusion, moderate maxillary anterior crowding, and healthy periodontal condition. Impressions of the upper arches were taken before archwire placement (T0) and at every 4 weeks (T1, T2, T3, and T4). For T1 and T2 stages, 0.014-in., and for T3 and T4 stages, 0.018-in. archwires were used. The primary outcome was the alignment efficiency assessed using Little's irregularity index. The secondary outcomes were arch width and incisor inclination changes. Data were analyzed using independent samples t test, repeated measures ANOVA, and Mann-Whitney U test. Marginal models were established for the estimation of coefficients. RESULTS: The anterior irregularity index reduction was mostly observed between T0 and T2 periods, which were respectively - 7.40 ± 0.50 mm (p < 0.001; 95% CI, - 8.94, - 5.85) and - 6.80 ± 0.55 mm (p < 0.001; 95% CI, - 8.49, - 5.12) for groups 1 and 2 (p < 0.001). With both wires, Little's irregularity index decreased over time, and the difference between the groups was not significant (p = 0.581; estimated effect size, 0.011). No statistically significant difference was found between the groups in terms of intercanine and intermolar width and incisor inclination changes. CONCLUSION: There were no significant between-group differences in alignment efficiency, arch width, and incisor inclination change. There was an increased alignment with 0.014-in. compared with 0.018-in. diameter archwire.


Assuntos
Níquel , Titânio , Adolescente , Cobre , Ligas Dentárias , Temperatura Alta , Humanos , Fios Ortodônticos
17.
Am J Orthod Dentofacial Orthop ; 156(6): 870-877, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31784021

RESUMO

INTRODUCTION: This study aimed to evaluate the ability of dental clinicians to predict posttreatment dental arch forms in patients with malocclusion with the aid of 3D imaging and digital software in comparison with a conventional method. METHODS: Pretreatment and posttreatment dental plaster casts of 100 patients (200 maxillary models and 200 mandibular models) were selected. Three orthodontists selected the best-fitted archwires among 5 commercially available preformed nickel-titanium archwires using 2 methods. In the conventional method, they fit the archwires to pretreatment casts, and in the digital method, they fit the scanned wire to a 3D digital model, using Ortho-Aid, a locally developed 3D software, using clinical bracket points as reference for wire fitness. The predicted posttreatment archwire in each method was compared with the best-fit archwire on the actual posttreatment model of each patient in both methods, and the level of agreement was calculated. The interobserver agreement between the 3 orthodontists in each method was evaluated using intraclass correlation coefficient and the Dahlberg formula. RESULTS: Orthodontists predicted the final treatment outcome in 50% of cases using the conventional method and 58% using the digital method. However, the range of method error was significantly higher in the conventional method (0.425-3.853 mm for the conventional vs 0.451-0.584 mm for the digital). CONCLUSIONS: Although the clinicians' ability to predict the final dental arch form after orthodontic treatment and the agreement between clinicians increased by the use of digital equipment, orthodontists can predict the final arch form in about 60% of patients.


Assuntos
Arco Dental , Imageamento Tridimensional , Fios Ortodônticos , Ortodontia Corretiva , Ligas Dentárias , Arco Dental/anatomia & histologia , Arco Dental/diagnóstico por imagem , Modelos Dentários , Previsões , Humanos , Mandíbula , Software
18.
Indian J Dent Res ; 30(4): 548-552, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31745051

RESUMO

Aim: The aim of this study was to evaluate and compare the surface characteristics of colored titanium molybdenum alloy archwires (purple-coated TMA and honey dew-coated TMA) and the regular titanium molybdenum alloy archwires. Materials and Methods: The experiment comprised three groups, Group I - regular TMA archwires, Group II - purple-coated TMA archwires, Group III - honey dew-coated TMA wires involving 21 samples each. The surface characteristics were assessed using scanning electron microscopy and optical profilometer. Results: The results were statistically analyzed using analysis of variance wherein Group I regular TMA wires exhibited a root mean square value of 148.071 nm and a standard deviation of 9.0027 nm followed by group II (purple-coated TMA wires) which showed a root mean square value of 84.095 nm with a standard deviation of 2.6005 nm, while group III (honey dew-coated TMA wires) was found to have a root mean square value of 71.681 nm with a standard deviation of 1.4645 nm on subjecting to optical profilometry. Conclusion: The surface roughness is higher for regular TMA wire exhibiting superior characteristic of color-coated TMA wires, especially honey dew-coated TMA wires over the regular and purple-coated TMA wires. This property of the archwires details regarding its application in both sliding and frictionless mechanics in retraction phase of fixed orthodontic treatment.


Assuntos
Fios Ortodônticos , Titânio , Ligas Dentárias , Teste de Materiais , Microscopia Eletrônica de Varredura , Aço Inoxidável , Propriedades de Superfície
19.
Int J Oral Maxillofac Implants ; 33(6): 1379-1388, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31711079

RESUMO

PURPOSE: The aim of this study was to explore the surface roughness and hardness of the implant head of orthodontic mini-implants made from different alloys before and after their in vitro exposure to agents for prevention of gingivitis, mucositis, and peri-implantitis: chlorhexidine and probiotics. MATERIALS AND METHODS: Three types of commercially available mini-implants were tested: 316 stainless steel, titanium Grade 5, and titanium Grade 23 (both Ti-6Al-4V alloys with the same atomic weight percentage of Ti, Al, and V, with the difference being in maximal reduction of O2 in Grade 23 to 0.13% of atomic weight). They were immersed in three experimental solutions: artificial saliva, saliva with probiotic bacteria Lactobacillus reuteri, and saliva with oral antiseptic chlorhexidine (CHX). Samples were immersed for 28 days, thermocycled, then stored in an incubator at 37°C. Surface roughness and microhardness on five samples of each of the three implant types were measured by atomic force microscopy and the Vickers method, respectively. RESULTS: Exposure of titanium implant Grade 5 to probiotics significantly increased roughness compared with other media (P < .005). Exposure to CHX significantly increased the roughness of steel implants (P < .05). Neither saliva, probiotic, nor CHX altered microhardness of titanium implants significantly. In steel implants, the exposure to CHX and probiotics decreased microhardness compared with unexposed implants (P < .031), but not in comparison to saliva. CONCLUSION: Probiotics seem to increase roughness of titanium mini-implants, while CHX seems to increase roughness of steel mini-implants. Only stainless steel implants had an altered, decreased hardness after exposure to CHX, although the same was found after their exposure to saliva. For patients undergoing orthodontic treatment with temporary anchorage units, CHX could be recommended for titanium, and probiotics for stainless steel mini-implants in oral-hygiene maintenance.


Assuntos
Clorexidina , Implantes Dentários , Probióticos , Corrosão , Ligas Dentárias , Humanos , Teste de Materiais , Aço Inoxidável , Propriedades de Superfície , Titânio
20.
Am J Orthod Dentofacial Orthop ; 156(5): 611-616, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31677669

RESUMO

INTRODUCTION: This study aimed to compare the microorganism adhesion on coated, partially coated, and uncoated orthodontic archwires after clinical use. The correlation between surface roughness (SR) and bacterial colonization was also evaluated. METHODS: A total of 48 archwire segments (0.016 × 0.022-in) were equally divided into 4 groups: nickel-titanium coated, nickel-titanium partially coated, uncoated stainless steel, and uncoated nickel-titanium. The archwires were randomly inserted in a split-mouth study design. After 4 weeks of clinical use, the total number of microorganisms adhering to the archwire was quantified and transformed into colony-forming units. SR was evaluated using a profilometer. A one-way and two-way ANOVA, post-hoc Tukey test, paired-samples t test, and Pearson correlation coefficient were used for statistical analysis. RESULTS: All the archwires presented microorganism adhesion, with the nickel-titanium-coated group demonstrating the highest value (P < 0.001). A statistically significant increase in SR was observed after clinical use for all groups (P < 0.05). No correlation between SR and bacterial adhesion was detected. CONCLUSIONS: Microorganism adhesion occurred on all of the archwires tested, especially on the esthetic fully coated. Because SR was not correlated with microorganism adhesion, future studies should evaluate the effect of surface free energy and superficial chemical changes on in-vivo microorganism adhesion.


Assuntos
Estética Dentária , Braquetes Ortodônticos , Fios Ortodônticos , Ligas Dentárias , Humanos , Teste de Materiais , Estudos Prospectivos , Aço Inoxidável , Propriedades de Superfície , Titânio
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