Using manual versus mechanized glide path instruments and ProTaper Gold versus ProTaper Next systems in curved canals: micro-CT study.

The aim of this study was to evaluate the root canal shaping effect of ProTaper Gold (PTG) versus ProTaper Next (PTN) instrumentation systems, and of a manual #15 K-type file (K15) versus the ProGlider (PG) mechanized instrument for glide path creation, in severely curved mesial canals. Twenty-four mandibular molars with two separate mesial canals were anatomically matched using computed tomographic scanning, and then divided into two groups (n=12) according to the glide path instrument used, either K15 or PG. In all teeth, the PTG system was used to prepare the mesiobuccal canal, and the PTN, the mesiolingual canal. The teeth were scanned by computed microtomography, before and after root canal preparation, and the values of the initial volume, final volume, volumetric variation, untouched walls, and canal transportation variables were determined. The data were analyzed using the two-way ANOVA test, and the Tukey test for multiple comparisons. There was no significant difference among the study groups regarding volumetric variation or root canal transportation, either in the cervical, middle or apical thirds, or in the entire root canal (p>0.05). In the apical third, the percentage of untouched walls was significantly higher in groups using K15 than in those using PG (p<0.05), namely 33.144% and 23.285%, respectively, irrespective of the instrumentation system. In the other regions, there was no difference between K15 and PG regarding this variable. It was concluded that PG was associated with a lower rate of untouched walls in the apical region than K15.

Using manual versus mechanized glide path instruments and ProTaper Gold versus ProTaper Next systems in curved canals: micro-CT study

Abstract The aim of this study was to evaluate the root canal shaping effect of ProTaper Gold (PTG) versus ProTaper Next (PTN) instrumentation systems, and of a manual #15 K-type file (K15) versus the ProGlider (PG) mechanized instrument for glide path creation, in severely curved mesial canals. Twenty-four mandibular molars with two separate mesial canals were anatomically matched using computed tomographic scanning, and then divided into two groups (n=12) according to the glide path instrument used, either K15 or PG. In all teeth, the PTG system was used to prepare the mesiobuccal canal, and the PTN, the mesiolingual canal. The teeth were scanned by computed microtomography, before and after root canal preparation, and the values of the initial volume, final volume, volumetric variation, untouched walls, and canal transportation variables were determined. The data were analyzed using the two-way ANOVA test, and the Tukey test for multiple comparisons. There was no significant difference among the study groups regarding volumetric variation or root canal transportation, either in the cervical, middle or apical thirds, or in the entire root canal (p>0.05). In the apical third, the percentage of untouched walls was significantly higher in groups using K15 than in those using PG (p<0.05), namely 33.144% and 23.285%, respectively, irrespective of the instrumentation system. In the other regions, there was no difference between K15 and PG regarding this variable. It was concluded that PG was associated with a lower rate of untouched walls in the apical region than K15.

Influence of Apical Patency on the Adaptation of the Master Filling Cone: A Cone-beam Computed Tomography Assessment.

Introduction: This study aimed to evaluate if the apical patency can influence the adaptation of the master cone of gutta-percha, quantifying the volume of voids and areas at the last 2 mm of the working length (WL). Materials and Methods: Sixty distobuccal canals of extracted upper molars were divided into 3 groups (n=20) based on the patency length (A: passed 1 mm beyond the apical foramen (AF), B: at the AF and C: 1 mm short of the AF) with the Easy ProDesign Logic 25/0.01 file. Each group was subdivided into 2 subgroups (n=10) based on the WL established to prepare the root canal (1: 1 mm short of the AF or 2: at the AF) with the Easy ProDesign Logic 25/0.05 file. After the scan, void volumes were calculated from the last 2 mm of the WL and void areas at 0 mm, 1 mm and 2 mm of the last of WL, as well as the relation between the tip and taper of the master cone with the amount of void volume and areas. To investigate statistically significant differences, we used the Kruskal-Wallis statistical test. Results: There were more voids in volume when patency was achieved 1 mm beyond the AF and the root canal preparation was conducted at 1mm short of the AF (A1 group). Furthermore, the same group showed more voids areas, mainly on the last millimeter of WL. Conclusion: Achieving apical patency at 1 mm beyond the AF followed by instrumentation 1 mm short of the AF created more voids between the master gutta-percha cone and the root canal wall, especially on the last millimeter of WL.

Retrospective study of endodontic treatment performed by undergraduate students using reciprocating instrumentation and single-cone obturation.

OBJECTIVES: The aim of this cross-sectional retrospective study was to evaluate radiographically the technical quality of root canal treatment performed by undergraduate students using reciprocating NiTi instrumentation and single-cone obturation. METHODS: Endodontic treatment on 1102 teeth performed by undergraduate students from the School of Dentistry of the University of Santa Cecilia (Brazil) was evaluated. All root canal preparations were performed using Reciproc files and were irrigated with 1% NaOCl. The root canal was filled with gutta-percha, along with AH Plus sealer, using the single-cone obturation technique. The technical quality of the root canal treatment was evaluated based on immediate postoperative radiographs. Distance between the end of the filling and the radiographic apex, the filling density, and the taper of the root filling was assessed. Inter-examiner agreement statistic (Kappa) and Chi-square statistic test were used for statistical evaluation of the results. Differences were considered statistically significant when p < 0.05. RESULTS: Anterior teeth, maxillary premolars, and molars presented better results than mandibular premolars and molars (p < 0.05). Mandibular premolars presented a high incidence of a short length of obturation (33.34%) and mandibular molars presented a high incidence of overfilling (6.55%). The majority of the treatment analyzed (62.46%) fulfilled all the criteria showing acceptable working length, taper, and density of obturation. Instrument fractures occurred in eighteen root canals (0.81%). CONCLUSIONS: The use of NiTi reciprocating instruments with the single-cone obturation technique provided an acceptable quality of endodontic treatment in the majority of the cases performed by undergraduate students.

Influence of heat treatment of nickel-titanium instruments on the accuracy of an electronic apex locator integrated with endodontic motor.

Context: Manufacturers have produced a wide variety of nickel-titanium (NiTi) alloys, but the available literature is limited on the accuracy of some integrated electronic apex locators (EAL) used with different NiTi heat treatments in working length (WL) determination. Aim: This study aims to evaluate ex vivo , the influence of different heat treatments of NiTi instruments, and the diameter of the apical preparation on the accuracy of an EAL used during root canal preparation using an integrated EAL and motor unit. Materials and Methods: Nineteen extracted human mandibular incisors were included in the study. The WL control was determined by the visual method. Instruments of Mtwo, Reciproc, Reciproc Blue, WaveOne Gold, Twisted File Adaptive, and Hyflex CM systems, with diameters from 0.25 mm to 0.50 mm, were used to measure WL during root canal preparation. The electrical resistivity of instruments with a diameter of 0.25 mm from each system was evaluated using an Inductance, Capacitance, and Resistance (LCR) meter. Statistical Analysis Used: Data were statistically analyzed using Fisher's exact test and Kruskal-Wallis test. Results: The different heat treatments and different diameters did not influence the precision of the EAL (P > 0.05). Conclusion: The heat treatment and the diameter of the apical preparation did not influence the accuracy of WL determination by an EAL integrated with the endodontic motor.

Optimum glide path motion is safer than continuous rotation of files in glide path preparation.

This study evaluated the resistance to flexural fatigue and torsional strength of files for glide path preparation in continuous rotation or Optimum Glide Path motion (OGP). ScoutRace 15.02 and ProGlider 16.02 files were used in a dynamic testing device during preparation of simulating curved root canals (40-degree curvature and 5 mm radius). For the torsional test, a machine was used to test torsion measured maximum torsional strength (N.cm). Two-way anova and Tukey's multiple comparisons test were used for statistical analysis. Files in OGP motion had a statistically better resistance to flexural fatigue (P < 0.05). ProGlider files took longer time to failure than ScoutRace files only when OGP was used (P < 0.05). The torsional test revealed that OGP produced significantly less torsional stress than rotary motions for both types of glide path files (P < 0.05) In conclusion, OGP motion increased substantially the mechanical safety of endodontic glide path files.

Resistência à fadiga cíclica dos instrumentos Reciproc e Mtwo nos movimentos rotatório e reciprocante / Resistance to cyclic fatigue of Reciproc and Mwto files on continuous rotation and reciprocating movements

Objetivo: O objetivo do presente estudo foi avaliar a influência da liga (NiTi convencional e M-Wire) e do movimento (reciprocante e rotação contínua) na resistência à fadiga cíclica. Métodos: Quinze limas Reciproc R25 (VDW GmbH, Munique, Alemanha) foram usadas em movimento reciprocante (MR), enquanto trinta limas Mtwo 25.07 (VDW GmbH, Munique, Alemanha) foram usadas em MR (n=15) ou em rotação contínua (RC) (n=15). Os instrumentos foram submetidos a ensaios dinâmicos movidos por motor elétrico, que permitiram reproduzir o movimento de pecking motion, a 300rpm de velocidade. Os instrumentos simularam a instrumentação de um canal radicular curvo com 40o e 5mm de raio de curvatura. A fratura dos instrumentos foi detectada por um sensor digital, e o tempo e o número de ciclos foram registrados. Os dados foram analisados estatisticamente pelos testes ANOVA e de Tukey (p<0,05). Resultados: Os instrumentos Reciproc R25 movidos por MR alcançaram número significativamente maior (p<0,05) de ciclos antes da fratura (1.777,68±334,2 ciclos), quando comparados aos instrumentos MT 25.07 movidos por MR (610,67±126,3 ciclos) ou RC (432,23±183,2 ciclos). Conclusões: O movimento reciprocante mostrou resistência à fadiga cíclica significativamente maior, e os instrumentos de NiTi M-Wire apresentaram maior resistência à fadiga cíclica do que os instrumentos rotatórios de NiTi convencional (AU).

Objective: The aim of present study was to evaluate the influence of alloy (conventional NiTi and M-Wire NiTi) and movement (reciprocating movement and continuous rotation) on resistance to cyclic fatigue. Methods: Fifteen Reciproc R25 files (VDW GmbH, Munich, Germany) were used in reciprocation motion (RM), while thirty MTwo 25/.07 files (VDW GmbH, Munich, Germany) were used either in RM (n=15) or in continuous rotation (CR) (n=15). The files were submitted to dynamic assays device moved by electric engine that allowed the reproduction of pecking motion under 300 rpm of speed. The files act simulating the instrumentation of a curved root canal with 40º and 5-mm of curvature radius. The fracture was detected by the device sensor and the time and number of cycles were obtained. Data were statistically analyzed by ANOVA and Tukeys tests (p<0.05). Results: The Reciproc R25 instruments moved by RM reached significantly higher number (p<0.05) of cycles before fracture (1777.68 ± 334.2 cycles) when compared with MTwo 25/.07 instruments moved by RM (610.67 ± 126.3 cycles) or CR (432.23 ± 183.2 cycles). Conclusions: The reciprocation motion showed significantly greater cyclic fatigue resistance and the M-Wire NiTi files showed higher cyclic fatigue resistance than conventional NiTi rotary files (AU).

Influence of an Audiovisual Resource on the Preoperative Anxiety of Adult Endodontic Patients: A Randomized Controlled Clinical Trial.

INTRODUCTION: The expectation of undergoing endodontic treatment can cause anxiety in patients. Anxiety is described as a transient emotional state closely related to pain, fear, and imbalance of the organism. The clinician commonly must use some type of tool to alleviate the patient's preoperative anxiety before treatment can be applied. The aim of this study was to evaluate the influence of an audiovisual resource on the preoperative anxiety of adult patients undergoing endodontic treatment. METHODS: One hundred sixty endodontic patients were randomly divided into experimental and control groups (n = 80) and then assessed at 2 preoperative time points separated by a 10-minute interval. After the first assessment, the patients in the experimental group watched a video of their own choice obtained from the Internet to provide them with a relaxing experience. In both groups and at both time points, the assessments consisted of collecting the patients' vital signs (diastolic blood pressure, systolic blood pressure, and heart rate) and data regarding their subjective perception of anxiety using a visual analog scale. RESULTS: There were no significant differences between the groups regarding the vital sign variation observed between the 2 assessment time points. However, the variation in the scores obtained on the visual analog scale was significantly greater in the experimental group (P < .05), indicating a greater reduction in the level of preoperative anxiety in this group. CONCLUSIONS: The preoperative use of an audiovisual resource was associated with a decrease in the perception of anxiety by patients undergoing endodontic treatment.

Root canal dressings for revascularization influence in vitro mineralization of apical papilla cells.

Endodontic revascularization is based on cell recruitment into the necrotic root canal of immature teeth after chemical disinfection. The clinical outcome depends on the ability of surviving cells from the apical tissue to differentiate and promote hard tissue deposition inside the dentinal walls. OBJECTIVE: To investigate the effect of calcium hydroxide (CH) and modified triple antibiotic paste (mTAP - ciprofloxacin, metronidazole and cefaclor) on the viability and mineralization potential of apical papilla cells (APC) in vitro . MATERIAL AND METHODS: APC cultures were kept in contact with CH or mTAP (250-1000 µg/mL) for 5 days, after which cell viability was assessed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Next, APCs were subjected to CH or mTAP at 250 µg/mL for 5 days before inducing the differentiation assay. After 14 and 21 days, calcium deposition was assessed by the Alizarin Red S staining method, followed by elution and quantification using spectrophotometry. Data were analyzed using ANOVA followed by Tukey post hoc test. RESULTS: CH induced cell proliferation, whereas mTAP showed significant cytotoxicity at all concentrations tested. APC treated with CH demonstrated improved mineralization capacity at 14 days, while, for mTAP, significant reduction on the mineralization rate was observed for both experimental periods (14 and 21 days). CONCLUSION: Our findings showed that CH induces cell proliferation and improves early mineralization, whereas mTAP was found cytotoxic and reduced the mineralization potential in vitro of APCs.

Cytotoxicity of intracanal dressings on apical papilla cells differ upon activation with E. faecalis LTA.

OBJECTIVE: The aim of this study was to investigate the cytotoxic effects of modified triple antibiotic paste and an experimental composition using calcium hydroxide on lipoteichoic acid (LTA)-primed apical papilla cells (APC). MATERIAL AND METHODS: Human APC were tested for in vitro cytotoxicity of modified Triple Antibiotic Paste (mTAP - Ciprofloxacin, Metronidazole and Cefaclor at 1:1:1) and of a paste of Ciprofloxacin, Metronidazole and Calcium hydroxide (CMC - 1:1:2) and modified CMC (mCMC - 2:2:1) by using MTT assay. The substances were reconstituted in DMEM at 1,000 µg/mL and » serially diluted before being kept in contact with cells for 1, 3, 5 and 7 days. Further, cells were primed with 1 µg/mL of Enterococcus faecalis LTA for 7 days prior to the viability test with 1,000 µg/mL of each substance. Statistical analysis was performed using one-way analysis of variance (ANOVA) and two-way ANOVA respectively followed by Tukey's post-test. Significance levels were set at p<0.05. RESULTS: In the first assay, the higher cytotoxic rates were reached by mTAP for all experimental periods. CMC was found toxic for APC at 5 and 7 days, whereas mCMC did not affect the cell viability. Only CMC and mCMC were able to induce some cellular proliferation. In the second assay, when considering the condition with medium only, LTA-primed cells significantly proliferated in comparison to LTA-untreated ones. At this context, mTAP and CMC showed similar cytotoxicity than the observed for LTA-untreated cells, while mCMC was shown cytotoxic at 7 days only for LTA-primed APC. Comparing the medications, mTAP was more cytotoxic than CMC and mCMC. CONCLUSION: mTAP showed higher cytotoxicity than CMC and mCMC and the effect of topic antimicrobials might differ when tested against apical papilla cells under physiological or activated conditions.

Root canal dressings for revascularization influence in vitro mineralization of apical papilla cells

Abstract Endodontic revascularization is based on cell recruitment into the necrotic root canal of immature teeth after chemical disinfection. The clinical outcome depends on the ability of surviving cells from the apical tissue to differentiate and promote hard tissue deposition inside the dentinal walls. Objective To investigate the effect of calcium hydroxide (CH) and modified triple antibiotic paste (mTAP - ciprofloxacin, metronidazole and cefaclor) on the viability and mineralization potential of apical papilla cells (APC) in vitro . Material and Methods APC cultures were kept in contact with CH or mTAP (250-1000 µg/mL) for 5 days, after which cell viability was assessed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Next, APCs were subjected to CH or mTAP at 250 µg/mL for 5 days before inducing the differentiation assay. After 14 and 21 days, calcium deposition was assessed by the Alizarin Red S staining method, followed by elution and quantification using spectrophotometry. Data were analyzed using ANOVA followed by Tukey post hoc test. Results CH induced cell proliferation, whereas mTAP showed significant cytotoxicity at all concentrations tested. APC treated with CH demonstrated improved mineralization capacity at 14 days, while, for mTAP, significant reduction on the mineralization rate was observed for both experimental periods (14 and 21 days). Conclusion Our findings showed that CH induces cell proliferation and improves early mineralization, whereas mTAP was found cytotoxic and reduced the mineralization potential in vitro of APCs.

Cytotoxicity of intracanal dressings on apical papilla cells differ upon activation with E. faecalis LTA

Abstract Objective The aim of this study was to investigate the cytotoxic effects of modified triple antibiotic paste and an experimental composition using calcium hydroxide on lipoteichoic acid (LTA)-primed apical papilla cells (APC). Material and Methods Human APC were tested for in vitro cytotoxicity of modified Triple Antibiotic Paste (mTAP - Ciprofloxacin, Metronidazole and Cefaclor at 1:1:1) and of a paste of Ciprofloxacin, Metronidazole and Calcium hydroxide (CMC - 1:1:2) and modified CMC (mCMC - 2:2:1) by using MTT assay. The substances were reconstituted in DMEM at 1,000 µg/mL and » serially diluted before being kept in contact with cells for 1, 3, 5 and 7 days. Further, cells were primed with 1 µg/mL of Enterococcus faecalis LTA for 7 days prior to the viability test with 1,000 µg/mL of each substance. Statistical analysis was performed using one-way analysis of variance (ANOVA) and two-way ANOVA respectively followed by Tukey's post-test. Significance levels were set at p<0.05. Results In the first assay, the higher cytotoxic rates were reached by mTAP for all experimental periods. CMC was found toxic for APC at 5 and 7 days, whereas mCMC did not affect the cell viability. Only CMC and mCMC were able to induce some cellular proliferation. In the second assay, when considering the condition with medium only, LTA-primed cells significantly proliferated in comparison to LTA-untreated ones. At this context, mTAP and CMC showed similar cytotoxicity than the observed for LTA-untreated cells, while mCMC was shown cytotoxic at 7 days only for LTA-primed APC. Comparing the medications, mTAP was more cytotoxic than CMC and mCMC. Conclusion mTAP showed higher cytotoxicity than CMC and mCMC and the effect of topic antimicrobials might differ when tested against apical papilla cells under physiological or activated conditions.

Pulse oximetry: a useful test for evaluating pulp vitality in traumatized teeth.

BACKGROUND AND AIM: Subjective pulp tests are not trustworthy, particularly in traumatized teeth, and may lead to inaccurate diagnosis. The use of an objective test such as pulse oximetry (PO) could be a more reliable method to properly evaluate pulp status in this condition. The aim of this study was to analyze the effectiveness of PO in determining pulp vitality in traumatized teeth based on oxygen saturation measurements (%SpO2 ). SUBJECTS AND METHODS: Fifty-nine permanent teeth that had undergone lateral luxation, and which were unresponsive to a cold spray test and were free from signs of necrosis, were selected and tested with PO at 7, 30 and 60 days after trauma. RESULTS: Fifty-nine teeth were tested. At 7 days after trauma, 8 teeth had low rates of oxygenation, compared to 10 at 30 and 60 days. Low rates were defined as a saturation reading ≤77%SpO2 . These teeth were assigned to the pulp necrosis (PN) group. The other 49 teeth were either considered to have healthy pulps (HP) (saturation ≥90%SpO2 ) or were assigned to a pulpitis (PP) group (saturation ≥78 to ≤89%SpO2 ). The 10 non-responsive teeth were followed up for 1 year and all exhibited indications for endodontic treatment. The other 49 teeth (HP or PP) began to show positive responses to the cold spray (after 3-9 months of follow up). No significant differences (P < 0.05) were detected between the three periods analyzed, but %SpO2 rates were significantly different (P < 0.01) between the groups (HP vs PP, HP vs PN and PP vs PN). CONCLUSIONS: PO can be extremely useful for the assessment of dental pulp status in traumatized teeth, particularly when these teeth do not show signs of PN and do not respond to cold tests.

Late Effects of Head and Neck Radiotherapy on Pulp Vitality Assessed by Pulse Oximetry.

INTRODUCTION: Radiation therapy (RT) of malignant tumors in the head and neck area may have damaging effects on surrounding tissues. The aim of this investigation was to evaluate the long-term effects of ionizing radiation on pulp vitality by measuring pulp oxygenation levels (%SpO2) in patients with history of RT of intraoral and oropharyngeal tumors 4-6 years after treatment. METHODS: In an experimental group RT (n = 90, history of RT) and a control group CON (n = 90, no history of RT), pulp vitality was assessed by measuring %SpO2 by using pulse oximetry and pulp sensitivity by cold thermal testing. All anterior teeth without history of endodontic therapy of the participants in group RT were measured (n = 693), regardless of the quadrant and the irradiated area. An equal number of anterior teeth were tested in group CON. RESULTS: There was no significant difference between the %SpO2 levels in group RT (92.7%; standard deviation, ± 1.83) and group CON (92.6%; standard deviation, ± 1.80). All teeth in RT and CON groups showed a positive response to the thermal test. All tested teeth were considered vital. CONCLUSIONS: Pulp %SpO2 was found to be within normal limits 4-6 years after RT. This suggests that RT may not have a long-term influence on pulp vitality, and reported short-term changes in pulpal microcirculation because of RT may be temporary.

Effect of different torques in cyclic fatigue resistance of K3 rotary instruments

Aim: To assess the effect of different torque values on cyclic fatigue resistance of K3 rotary nickel-titanium (NiTi) files. Methods: Eighty K3 files, size 25 mm, taper 0.04 were divided in 4 groups according to different torques (0.5, 1, 2 and 6 Ncm) and were submitted to a cyclic fatigue test. This test was performed with a device that allowed the file to rotate inside a stainless steel artificial curved canal, simulating the pecking motion. Files rotated until fracture occurred and time to failure was recorded in seconds with a stopwatch. Data were analyzed by ANOVA and Tukey tests (p<0.05). Results: All groups were compared and only the group of 6 N.cm showed statistically significant difference (p=0.0002). Conclusions: For #25.04 K3 files, the evaluated torques up to 2 N.cm had no influence on cyclic fatigue resistance. Using 6 N.cm torque value resulted in lower resistance to cyclic fatigue.

Not all electronic foramen locators are accurate in teeth with enlarged apical foramina: an in vitro comparison of 5 brands.

INTRODUCTION: Electronic working length measurement during root canal treatment in teeth with enlarged apical foramina is a challenge. The aims of this in vitro study were (1) to assess the influence of foramen widening on the accuracy of 5 different electronic foramen locators (EFLs) and (2) to compare the accuracy of EFLs in different foramen sizes. METHODS: The following EFLs were used: MiniApex, Root ZXII, iPex, Propex II, and Elements Apex Locator. Each EFL was used in 3 groups (n = 20) of extracted teeth, with foramen diameters of 0.27 mm (G27), 0.47 mm (G47), and 0.72 mm (G72). Working length was measured according to manufacturer's instructions and compared with visual measurements (control method). Results were classified as accurate (equal or differences ≤ 0.05 mm) or inaccurate (differences > 0.5 mm). RESULTS: In G27, all EFLs yielded accurate findings (intragroup reliability; Fisher exact test, P < .05), compared with only MiniApex, Root ZXII, and Elements Apex Locator in G47 and G72. MiniApex, Root ZXII, and Elements Apex Locator were similarly accurate regardless of foramen size. iPex and Propex II were the least accurate among the devices tested, and foramen diameter influenced their accuracy, with greater diameters yielding poorer EFL performance. CONCLUSIONS: Foramen diameter did not influence the accuracy of MiniApex, Root ZXII, and Elements Apex Locator EFLs. iPex and Propex II showed decreased accuracy as foramen size increased.

Testes pulpares: da "era do gelo" à "era tecnológica" / pulp tests: the \"Ice Age\" to the \"technological age\"

Os testes pulpares fazem parte dos exames mais utilizados para identificar a saúde da polpa dentária, e podem ser qualificados como: testes de sensibilidade (como os testes térmicos e elétricos) e testes de vitalidade (como a Fluxometria Laser Doppler e a Oximetria de pulso). Os testes de sensibilidade, apesar de serem os mais utilizados, apresentam limitações importantes, pois avaliam a resposta nervosa sensorial à aplicação de estímulos e apenas pressupõem a condição de vitalidade da polpa. Já os testes de vitalidade, que analisam o suprimento sanguíneo ou o tecido vascular, mesmo com algumas limitações, são mais objetivos e avaliam o real estado fisiológico da polpa. Este trabalho discute o panorama atual da utilização dos testes pulpares, revê os fatores condicionantes da avaliação da polpa, mostra as vantagens e dificuldades de ambos testes de sensibilidade e vitalidade, e analisa as perspectivas do uso da tecnologia no diagnóstico endodôntico...

Among the most commonly used exams to identify the health of dental pulp are the pulp tests, which can be qualified as sensitivity tests (such as thermal and electrical test) or vitality tests (such as Laser Doppler Flowmetry and Pulse Oximetry). Sensitivity tests, despite being the most widely used ones, have important limitations, since they assess the responses of sensory nerves to an applied stimulus and can only presuppose the pulp vitality. Vitality tests, which analyze the blood supply or the vascular tissue, even with some limitations, are more objectives and can assess the real physiological status of the pulp. This work discusses the current panorama of the use of pulp tests, and revises the determining factors of pulp evaluation, showing the advantages and difficulties of both tests, sensitivity and vitality, and analyzing the prospects for the usage of technology in endodontic diagnosis...

Clinical diagnosis of pulp inflammation based on pulp oxygenation rates measured by pulse oximetry.

INTRODUCTION: The objective of this study was to investigate correlations between pulp oxygenation rates (%SpO(2)) and clinical diagnoses of reversible pulpitis (RP), irreversible pulpitis (IP), or pulp necrosis (PN). METHODS: Sixty patients who presented with a tooth with endodontic pathology were grouped according to a clinical diagnosis of either RP (n = 20), IP (n = 20), or PN (n = 20). The clinical diagnosis was based on the patient's dental history, periapical radiographs, clinical inspection, and percussion and thermal sensitivity testing. Pulse oximetry (PO) was used to determine pulp oxygenation rates. For every patient, one additional endodontically treated tooth (negative control [NC], n = 60) and one additional healthy tooth with healthy pulp status (positive control [PC], n = 60) were evaluated. Analysis of variance, the Tukey HSD test, and the Student's t test were used for statistical analysis. RESULTS: The mean %SpO(2) levels were as follows: RP: 87.4% (standard deviation [SD] ±2.46), IP: 83.1% (SD ±2.29), PN: 74.6% (SD ±1.96), PC: 92.2% (SD ±1.84), and NC: 0% (SD ±0.0). There were statistically significant differences between RP, IP, and PN compared with NC and PC and between RP, IP, and PN (all P ≤ .01). CONCLUSIONS: The evaluation of pulp oxygenation rates by PO may be a useful tool to determine the different inflammatory stages of the pulp to aid in endodontic diagnosis.

Resistance to flexural fatigue of Reciproc R25 files under continuous rotation and reciprocating movement.

INTRODUCTION: The aim of the present work was to evaluate the resistance to flexural fatigue of Reciproc R25 nickel-titanium files, 25 mm, used in continuous rotation motion or reciprocation motion, in dynamic assays device. METHODS: Thirty-six Reciproc R25 files were divided into 2 groups (n = 18) according to kinematics applied, continuous rotary (group CR) and reciprocation motion (group RM). The files were submitted to dynamic assays device moved by an electric engine with 300 rpm of speed that permitted the reproduction of pecking motion. The files run on a ring's groove of temperate steel, simulating instrumentation of a curved root canal with 40° and 5 mm of curvature radius. The fracture of file was detected by sensor of device, and the time was marked. The data were analyzed statistically by Student's t test, with level of significance of 95%. RESULTS: The instruments moved by reciprocating movement reached significantly higher numbers of cycles before fracture (mean, 1787.78 cycles) when compared with instruments moved by continuous rotary (mean, 816.39 cycles). CONCLUSIONS: The results showed that the reciprocation motion improves flexural fatigue resistance in nickel-titanium instrument Reciproc R25 when compared with continuous rotation movement.

Nd:YAG laser irradiation effect on apical intracanal dentin - a microleakage and SEM evaluation.

The purpose of this in vitro study was to evaluate the effect of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser irradiation on intracanal dentin surface by SEM analysis and its interference in the apical seal of filled canals. After endodontic treatment procedures, 34 maxillary human incisors were randomly assigned to 2 groups. In the negative control group (n=17), no additional treatment was performed and teeth were filled with vertically condensed gutta-percha; in the laser-treated group (n=17), the root canals were irradiated with Nd:YAG laser (1.5 W, 100 mJ, 15 Hz) before filling as described for the control group. Two specimens of each group were prepared for SEM analysis to evaluate the presence and extent of morphological changes and removal of debris; the other specimens were immersed in 0.5% methylene blue dye (pH 7.2) for 24 h for evaluation of the linear dye leakage at the apical third. SEM analysis of the laser-treated group showed dentin fusion and resolidification without smear layer or debris. The Student's t-test showed that the laser-treated group had significantly less leakage in apical third than the control group. Within the limitations of this study, it may be concluded that the morphological changes on the apical intraradicular dentin surface caused by Nd:YAG laser resulted in less linear dye apical leakage.