Influence of the timing of periodontal intervention on periapical/periodontal repair in endodontic-periodontal lesions: a systematic review.

INTRODUCTION: This study is aimed at answering the following question: "Does the timing of periodontal intervention influence the periapical/periodontal repair in endodontic-periodontal lesions?". MATERIAL AND METHODS: Six electronic databases were systematically searched for studies published up to April 2022, without restriction of language or year of publication, following the PIOS strategy: (P) adult patients with a diagnosis of endodontic-periodontal lesions, (I) endodontic and periodontal treatment, (O) periapical and periodontal healing, and (S) clinical studies. Risk of bias assessment was performed with the revised Cochrane risk of bias tools for randomized trials (RoB 2) and non-randomized interventions (ROBINS-I). The overall quality of evidence was assessed through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool. RESULTS: Three studies (one prospective, one retrospective, and one randomized clinical trial) were included in the present review. Non-randomized studies had a critical and serious risk of bias. The randomized clinical trial had some concerns risk of bias. Non-randomized studies reported that the endodontic intervention should be performed previous to the periodontal intervention. Randomized clinical trial reported improvements when endodontic and periodontal interventions were performed simultaneously. GRADE analysis showed a very low quality of evidence for both randomized and nonrandomized studies. CONCLUSIONS: Based on the evidence from the included studies, although it is suggested that the endodontic treatment should be performed prior to periodontal treatment, it is not possible to assure the best treatment sequence for endodontic-periodontal lesions. CLINICAL RELEVANCE: Evidences suggests that although the endodontic intervention should be the first therapy of choice, it was not possible to specify the best time to perform the periodontal intervention.

Do NSAIDs used prior to standard inferior alveolar nerve blocks improve the analgesia of mandibular molars with irreversible pulpitis? An umbrella review.

INTRODUCTION: The aim of the present umbrella review was to answer the following question: "Does the use of NSAIDs as premedication increase the efficacy of the standard inferior alveolar nerve block on teeth with symptomatic irreversible pulpitis?" MATERIAL AND METHODS: Systematic reviews with and without meta-analyses that evaluated the influence of premedication on anesthetic efficacy of the inferior alveolar nerve in symptomatic irreversible pulpitis of mandibular molars were searched in six electronic databases (MEDLINE/PubMed, Scopus, Web of Science, Cochrane Library, EMBASE, and Grey Literature Reports), without the restriction of language or year of publication. A Measurement Tool to Assess systematic Reviews (AMSTAR 2) was used to evaluate the quality of the included studies. RESULTS: Twelve systematic reviews were included. Only one did not perform a meta-analysis. The AMSTAR 2 overall confidence ranged from very low to high. In general, the main findings of the systematic reviews were that non-steroidal anti-inflammatory drugs (e.g., ibuprofen, oxicam, diclofenac, association of ibuprofen with acetaminophen, and ketorolac) increased the success rate of the inferior alveolar nerve block. CONCLUSIONS: From the "very low" to "high"-quality evidence available, this umbrella review concluded that NSAIDs as premedication acts through cyclooxygenase pathways and block the synthesis of specific prostaglandins that complicate the mechanism of action of the anesthesia, improving its success rate. CLINICAL RELEVANCE: Non-steroidal anti-inflammatory drugs can increase the success rate of the anesthetic technique of inferior alveolar nerve block efficacy in situations of mandibular molars with symptomatic irreversible pulpitis.

Do orthodontic movements of traumatized teeth induce dental pulp necrosis? A systematic review.

INTRODUCTION: Usually, orthodontic movements encompass children and young adult patients, which are more susceptible to the occurrence of traumatic dental injuries. It is necessary to understand whether the effects of orthodontic movements on traumatized teeth could induce pulp necrosis. The aim of this study was to answer the following question: "Do orthodontic movements of traumatized teeth induce dental pulp necrosis?". MATERIAL AND METHODS: Searches were performed for studies published up to May 11, 2023, in the MEDLINE/PubMed, Cochrane Library, Scopus, SciELO Citation Index, Web of Science, EMBASE, and Grey Literature Report databases, without restriction for language or year of publication. The revised Cochrane risk of bias tools for nonrandomized interventions (ROBINS-I) was used to assess the quality of the included studies. The overall quality of evidence was assessed through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool. RESULTS: Of 2671 potentially relevant studies, five were included. Four were classified as having a moderate risk of bias and one as a serious risk of bias. It was reported a higher susceptibility to pulp necrosis in teeth subjected to orthodontic movements with history of trauma involving periodontal tissues. Additionally, orthodontic movements of traumatized teeth with total pulp obliteration had an increased risk of pulp necrosis. GRADE analysis presented a moderate certainty of evidence. CONCLUSIONS: An increased risk for pulp necrosis when traumatized teeth are subjected to orthodontic movements was verified. However, this is based on evaluations performed with subjective tests. Further well-designed studies are necessary to confirm this trend. CLINICAL RELEVANCE: Clinicians must be aware of the possibility of pulp necrosis. However, endodontic treatment is recommended when verified signs and symptoms of pulp necrosis.

Effect of music during endodontic treatment on patients' anxiety: a systematic review of randomized clinical trials.

OBJECTIVES: Endodontic treatment is one of the most fearful procedures among dentistry, and the use of music during the procedure has been evaluated to control patients' anxiety. This systematic review has been conducted to provide a synthesis of the state of knowledge in this field and aimed to answer the following question: "Can music therapy reduce patient's state anxiety during endodontic treatment?". METHODS: A search was performed in six electronic databases (PubMed, Cochrane Library, Scopus, Web of Science, EMBASE, and Open Gray) for articles published until April 2022. The eligibility criteria, based on the PICOS strategy, were as follows: (P) patients undergoing endodontic treatment; (I) exposure to music; (C) no music; (O) patients' anxiety; (S) only randomized clinical trials. The risk of bias was analyzed according to the Cochrane Risk of Bias tool for randomized controlled trials (RoB 2). The strength of evidence from the included studies was assessed using the Grading of Assessment, Development, and Assessment Recommendations (GRADE) tool. RESULTS: Five eligible studies were retrieved. A low to high risk of bias was verified. Descriptive analysis showed an effect in favor of music intervention, with differences among state anxiety, heart rate and blood pressure. CONCLUSIONS: With a very low quality of evidence, dental care professionals may consider playing background music during endodontic treatment since it is a cost-effective and easy alternative to trying to reduce dental anxiety. CLINICAL RELEVANCE: Five studies were included in this systematic review and showed, with a very low quality of evidence, that music may reduce state anxiety levels on patients during root canal treatment.

Head and neck radiotherapy effects on the dental pulp vitality and response to sensitivity tests: A systematic review with meta-analysis.

BACKGROUND: Experimental studies are controversial regarding the effects of radiotherapy for head and neck cancer (HNC) on the dental pulp. Therefore, a systematic review of clinical studies is necessary to investigate whether alterations in pulp status occur. OBJECTIVES: To evaluate the evidence on radiotherapy for HNC and pulp status. METHODS: A systematic search of articles published until November 2021 was performed in the MEDLINE/PubMed, Cochrane Library, Web of Science (All Databases), Scopus, EMBASE, and Open Grey databases. The eligibility criteria were based on the PICOS strategy, as follows: (P) vital teeth of adult patients with intraoral and/or oropharyngeal cancer; (I) radiotherapy; (C) control group or values of the same tooth before radiotherapy (basal values); (O) pulpal status after radiotherapy; and (S) clinical studies. The Cochrane Risk of Bias in Nonrandomized Studies of Interventions tool was used to assess the quality of the included studies. Meta-analyses were performed using fixed and random effects. The overall quality of evidence was assessed through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool. RESULTS: Six studies were included for qualitative analysis. Five were classified as serious risk of bias and one as moderate risk of bias. Four studies reported altered pulp responses to cold thermal tests after radiotherapy initiation. Meta-analyses were performed using three included studies. From these, all were included in the meta-analysis for pulp response values to cold sensitivity test immediately after radiotherapy initiation (risk ratio: 0.00 [CI: 0.00, 0.02], p < .00001; I2  = 0%); and two in the meta-analysis for pulp response values to cold sensitivity test after 4-5 months of radiotherapy (risk ratio: 0.01 [CI: 0.00. 0.06], p < .00001; I2  = 0%). Two reported progressively higher readings to pulp response in the electrical test after radiotherapy initiation (mean difference: -11.46 [-13.09, -9.84], p < .00001; I2  = 68%). Two studies demonstrated a pulp oxygen saturation (SpO2 ) decrease at the end of radiotherapy; and an increase after 4-6 months of radiotherapy beginning. And other demonstrated normal dental pulp SpO2 4-6 years after treatment. GRADE analysis presented a moderate certainty of evidence. DISCUSSION: This review verified that radiotherapy for HNC causes significant alterations on the dental pulp responses, but does not seem to induce pulp necrosis. Significant limitations regarding controlling for confounding factors, classification of interventions, and measurement of outcomes were verified, evidencing the need for well-designed studies. CONCLUSIONS: This systematic review demonstrated that radiotherapy for HNC induced significant changes in the pulp response with moderate quality of evidence. Such altered responses cannot determine pulp status accurately.

Comparison between isolated and associated with codeine acetaminophen in pain control of acute apical abscess: a randomized clinical trial.

OBJECTIVES: The study aimed to compare the acetaminophen administration efficacy or its combination with codeine for pain control in acute apical abscesses cases. MATERIALS AND METHODS: Thirty-nine patients who sought emergency treatment in the Faculty of Dentistry of the Federal University of Rio Grande do Sul were included, all of them with acute apical abscess diagnosis. These patients were divided into two groups: acetaminophen group-prescription of acetaminophen (1000 mg) and acetaminophen-codeine group-prescription of acetaminophen (1000 mg) + codeine (30 mg), both with oral intake every 6 h for 3 days. The pain scores were recorded by the patients on their own at 6, 12, 24, 48, and 72 h after finishing clinical assistance, by filling a pain evolution journal, containing a visual analogue scale (VAS). Student t test was conducted to investigate different mean ages between groups 1 and 2. A comparison of weight and means of initial pain scores between groups was carried out using the Mann-Whitney U test. Chi-square test was performed to compare gender, affected tooth, education, initial swelling, and frequency of adverse effect between test and control groups. Mann-Whitney U test was applied to compare groups in the same period. Friedman's test was used to compare results from the same group over time. RESULTS: Both groups showed score reduction over time (P < 0.05). Paracetamol-codeine group showed significant pain score reduction at 48 h registers when compared to baseline and at 6 h scores (P < 0.05). Further, pain scores at 72 h were significantly lower, when compared to the baseline, at 6 h, and at 12 h scores (P < 0.05). Acetaminophen group showed significant pain score reduction observed at 72 h, when compared to the baseline and at 6 h scores (P < 0.05). There were no significant differences in pain score reduction over time between groups (P > 0.05). There was no difference between the groups regarding the frequency of adverse reactions (P > 0.05). CONCLUSION: Both medications were effective for pain control in acute apical abscess cases. The findings might have inferred in pain control of acute apical abscess associated pain in patients who used an antibiotic drug. External validity of the findings for acute apical abscess cases with no need for an antibiotic prescription is uncertain. CLINICAL RELEVANCE: This paper suggests acetaminophen 1000 mg can be used for pain control in the treatment of acute apical abscess associated with systemic manifestation.

Influence of cervical preflaring and root canal preparation on the fracture resistance of endodontically treated teeth.

BACKGROUND: Evaluate the fracture resistance of endodontically treated teeth after cervical preflaring and root canal preparation and to assess the volume of the root canal and the amount of remaining root dentin before and after cervical preflaring. METHODS: Forty-four mandibular incisors were selected using micro-CT scanning and distributed into 4 groups (n = 11) according to the instrument used for cervical preflaring: control group - no cervical preflaring; Gates Glidden - burs size #2 and #3; WXN - 25.07 Navigator instrument; and Easy - 25.08 ProDesign S instrument. Coronal opening was performed, and the canals were prepared with Wave One Gold Primary and filled with an epoxy-resin based sealer and gutta-percha cones. Micro-CT scans were performed before and after root canal instrumentation. All images were reconstructed and assessed for the thickness of mesial and distal root dentin at 3 mm and 5 mm from the cement -enamel junction and for the volume of cervical portion of the canal after preparation. Fracture resistance test was performed applying compressive loads at a crosshead speed of 0.5 mm/min, applied on the palatal aspect of specimens at 135° along the long axis of the tooth. The data were analyzed using ANOVA and Tukey's test (P = .05). RESULTS: Cervical preflaring and canal preparation reduced the dentin thickness (P < .05) and increased the canal volume (P < .05) in all groups at 3 mm an 5 mm. Cervical preflaring with Gates Gliden burs reduced the fracture resistance of endodontically treated teeth (P < .05). CONCLUSIONS: All instruments reduced the dentin thickness and increased the canal volume in the cervical at 3 mm and 5 mm. Gates Glidden reduced fracture resistance of mandibular incisors submitted to cervical preflaring, whereas NiTi instruments did not. CLINICAL RELEVANCE: Cervical preflaring assumes particular importance previously to the root canal preparation because it minimizes the occurrence of operative accidents, and permits more accurate determination of working length and the apical diameter.

Comparison of efficiency of the retreatment procedure between Wave One Gold and Wave One systems by Micro-CT and confocal microscopy: an in vitro study.

INTRODUCTION: To compare, by Micro-CT and confocal laser scanning microscopy (CLSM), the ability of the Wave One Gold and Wave One systems to remove filling material from mesial canals of mandibular molars, effective time spent; quantity of extruded material, and percentage of sealer in the dentinal tubules after retreatment and re-obturation procedures. MATERIALS AND METHODS: Ten first mandibular molars (n = 20 mesial canals) were prepared and filled with gutta-percha and Endofill sealer mixed with Rhodamine B dye using the single cone technique. After 7 days, the canals were scanned using a high-definition micro-computer tomography with 19-mm voxel size and divided into two groups (n = 10) according to the system used in retreatment: group 1, Wave One (WO), and group 2, Wave One Gold (WG). After removing filling material with the primary file of each system, the WO 40/.08 and WG 35/.06 files were used. After using each file, a new scanning was performed and the residual filling material and extruded filling material were measured. The effective time spent to remove the canal filling was measured after each instrument. After retreatment, the teeth were re-obturated with gutta-percha and AH Plus sealer mixed with fluorescein dye using the single-cone technique. The roots were sectioned at 2, 4 and 6 mm and analysed by CLSM to measure the percentage of remaining sealer and the sealer of the new root canal filling. The data were statistically compared (P < 0.05). RESULTS: Both systems presented a similar volume of filling material remaining in the canals after the use of the two instruments, similar residual and new material in the dentinal tubules, and similar extrusion of material (P > 0.05). When using WO 25, the operator spent significantly less effective time than when using WG 25 (P < 0.05); however, use of WG 35 and WO 40 required a similar time to remove filling material from the canals (P > 0.05). CONCLUSIONS: Neither of the two systems removed all the filling material. The WG system presented similar ability in removing filling and extruded material in comparison with WO system. The effective time spent was shorter for WO 25 than for WG 25. CLINICAL RELEVANCE: Wave One Gold can be an alternative to perform retreatment considering that in comparison with Wave One, there was no difference in filling material removal capacity and extruded materials. There was only difference in the effective time spent, in which the operator spent more time with WG 25 than with WO 25.

Effect of temperature on the cyclic fatigue resistance of thermally treated reciprocating instruments.

OBJECTIVES: The aim of this study was to evaluate the impact of body temperature on the cyclic fatigue resistance of different NiTi alloys used for the manufacturing of Reciproc Blue R25 (RB 25.08; VDW, Munich, Germany), X1 Blue File 25 (X1 25.06; MK Life Medical and Dental Products, Porto Alegre, Brazil) and WaveOne Gold Primary (WOG 25.07; Dentsply Maillefer, Ballaigues, Switzerland). MATERIALS AND METHODS: Sixty instruments of the RB 25.08, X1 25.06 and WOG 25.07 systems were used (n = 20). Cyclic fatigue tests were performed at room temperature (20° ± 1 °C) and at body temperature (37° ± 1 °C). The instruments were reciprocated until fracture occurred in an artificial stainless steel canal with a 60° angle and a 5-mm radius of curvature. The time to fracture (TTF) was recorded. Also, the number of cycles to fracture (NCF) was calculated. Data were analysed using one-way ANOVA and Tukey's tests for inter-group comparison at both temperatures and for the reduction of cyclic fatigue at body temperature. For intra-group comparison at the different temperatures, the unpaired t test was used. RESULTS: The cyclic fatigue test at 20 °C showed that RB 25.08 and X1 25.06 presented significantly higher TTF and NCF than WOG 25.07 (P < 0.05). At 37 °C, all groups presented significant reduction of TTF and NCF (P < 0.05). RB 25.08 presented significant higher TTF than WOG 25.07 (P < 0.05). Regarding the NCF, there was no significant difference among the groups (P > 0.05). The WOG 25.07 presented the lowest percentage reduction of cyclic fatigue (P < 0.05). CONCLUSION: The body temperature treatment caused a marked reduction of the cyclic fatigue resistance for all reciprocating instruments tested. The RB 25.08 and X1 25.06 systems presented similar results at both temperatures tested. However, WOG 25.07 presented the lowest percentage reduction in fatigue resistance at body temperature. CLINICAL RELEVANCE: The cyclic fatigue resistance of NiTi reciprocating instruments has been evaluated at room temperature. However, the fatigue resistance significantly decreases upon exposure to body temperature, which could affect the mechanical behaviour of the NiTi instruments during root canal preparation.

Effect of fiber post space irrigation with different peracetic acid formulations on the bond strength and penetration into the dentinal tubules of self-etching resin cement.

STATEMENT OF PROBLEM: The post space must be irrigated with solutions that do not interfere with the bond strength and enhance penetration into the dentinal tubules of self-etching resin cement. Which solution is best is unclear. Peracetic acid with different formulations appears to be a good option. PURPOSE: The purpose of this in vitro study was to evaluate the effect of irrigating the fiber post space by using 1% peracetic acid (PA) at low (LH) or high (HH) hydrogen peroxide concentration on the bond strength and penetration into the dentinal tubules of RelyX U200 self-etching resin cement. MATERIAL AND METHODS: After intraroot preparation for fiber posts in 60 endodontically treated teeth, the specimens were divided into 4 groups (n=15) according to the irrigation protocol: CG (control), distilled water; NA (NaOCl), 2.5% sodium hypochlorite; LHPA, PA with a low concentration of hydrogen peroxide; and HHPA, PA with a high concentration of hydrogen peroxide. The fiber posts were then cemented with self-etching resin cement labeled with rhodamine. Cross sections of the thirds were obtained by confocal scanning microscopy and submitted to the push-out and cement penetration tests. The data obtained in the push-out tests were evaluated by using ANOVA and the Tukey post hoc test, and those data obtained in the confocal screening were evaluated by using the Kruskal-Wallis and Dunn (Bonferroni correction) tests (α=.05). RESULTS: Bond strength values in the cervical third of the CG were higher than those in NA (P=.035) but similar to those of the other groups (P=.05). In the other thirds, CG and LHPA values were similar to one another (P=.05) but higher than those of NA and HHPA (P<.001). The penetration rate assessed by confocal scanning microscopy revealed similar results in the cervical third for all groups (P=.075), except for NA which provided the lowest penetration. In the remaining thirds, CG and LHPA provided the highest penetration rate (P=.015). CONCLUSIONS: The LHPA group had no negative effects on the bond strength and penetration into the dentinal tubules of the self-etching resin cement.

Correction to: Cyclic fatigue and torsional strength of three different thermally treated reciprocating nickel-titanium instruments.

The original version of this article contained a mistake. The name Jader Carvalho Pinto should have been Jader Camilo Pinto.

Cyclic fatigue and torsional strength of three different thermally treated reciprocating nickel-titanium instruments.

OBJECTIVES: The aim of this study was to evaluate the cyclic and torsional fatigue resistance of the reciprocating single-file systems Reciproc Blue 25.08 (VDW GmbH, Munich, Germany), Prodesign R 25.06 (Easy Dental Equipment, Belo Horizonte, Brazil), and WaveOne Gold 25.07 (Dentsply/Tulsa Dental Specialties, Tulsa, OK, USA). MATERIALS AND METHODS: Sixty reciprocating instruments of the systems Reciproc Blue R25 (RB #25 .08 taper), Prodesign R (PDR #25 .06 taper), and WaveOne Gold (WOG #25 .07 taper) (n = 20) were used. Cyclic fatigue resistance testing was performed by measuring the time to failure in an artificial stainless steel canal with a 60° angle of curvature and a 5-mm radius located 5 mm from the tip (n = 10). The torsional test (ISO 3630-1) evaluated the torque and angle of rotation at failure of new instruments (n = 10) in the portion 3 mm from the tip. The fractured surface of each fragment was also observed using scanning electron microscopy (SEM). In addition, a supplementary examination was performed to measure the cross-sectional area of each instrument 3 and 5 mm from the tip. The data were analyzed using one-way ANOVA and Tukey's test, and the level of significance was set at 5%. RESULTS: The cyclic fatigue resistance values of PDR 25.06 were significantly higher (P < 0.05). RB 25.08 showed higher fatigue resistance than WOG 25.07 (P < 0.05). The torsional test showed that PDR 25.06 had lower torsional strength (P < 0.05). No differences were observed between RB 25.08 and WOG 25.07 (P > 0.05). PDR 25.06 showed higher angular rotation values than RB 25.08 and WOG 25.07 (P < 0.05). RB 25.08 presented higher angular rotation than WOG 25.07 (P < 0.05). The cross-sectional area analysis showed that PDR 25.06 presented the smallest cross-sectional areas at 3 and 5 mm from the tip (P < 0.05). CONCLUSION: PDR 25.06 presented the highest cyclic fatigue resistance and angular rotation until fracture compared to RB 25.08 and WOG 25.07. In addition, RB 25.08 and WOG 25.07 had higher torsional strength than PDR 25.06. CLINICAL RELEVANCE: In endodontic practice, thermally treated reciprocating instruments have been used for the root canal preparation of curved and constricted canals; therefore, these instruments should present high flexibility and suitable torsional strength to minimize the risk of instrument fracture.

Effects of different peracetic acid formulations on post space radicular dentin.

STATEMENT OF PROBLEM: The optimal irrigating solution with antimicrobial and dentin cleansing properties for post space preparation for fiber posts is unclear. Peracetic acid is one option but is available in various chemical formulations that require evaluation. PURPOSE: The purpose of this in vitro study was to evaluate dentin surface cleanliness based on the presence of a smear layer and the number of open dentin tubules. It also investigates the chemical composition of residues after canal irrigation with a 1% peracetic acid solution (PA) at low or high concentration of hydrogen peroxide during the preparation of intracanal fiber posts. MATERIAL AND METHODS: After filling the root canals of 40 mandibular incisors, a rotary instrument was used for intracanal preparation to place fiber posts. The teeth were divided into 4 groups (n=10) according to the post space irrigation protocol as follows: CG (control): distilled water; NA (NaOCl): 2.5% sodium hypochlorite; LH: PA with low concentration of hydrogen peroxide; and HH: PA with high concentrations of hydrogen peroxide. After irrigation, the teeth were sectioned, and the intracanal dentin surface was subjected to analysis using energy dispersive spectroscopy to evaluate chemical composition and to scanning electron microscopy (×500) to evaluate the presence of the smear layer. The number of open dentin tubules was measured by scanning electron microscopy analysis (×2000) using photo-editing software. ANOVA and the Tukey test (α=.05) were used to evaluate the data, except for the presence of a smear layer, for which the Kruskal-Wallis and Dunn tests were used (α=.05). RESULTS: The highest concentrations of oxygen in the dentin residues were detected in LH and HH (P<.05); CG and NA showed similar oxygen concentrations (P>.05). NA had a higher concentration of chlorine (P<.05), whereas LH had a lower amount of smear layer and a larger number of open dentin tubules than the other groups (P<.05). These were equivalent to each other (P>.05), except for HH, which also had a larger number of open dentin tubules than CG and NA (P<.05). CONCLUSIONS: PA 1% with a low concentration of hydrogen peroxide yielded a lower amount of smear layer and a larger number of open dentin tubules in the dentin of the post space when compared with PA 1% with a high concentration of hydrogen peroxide, despite maintaining a similar oxygen concentration in these dentin residues.

Final irrigation protocols may affect intraradicular dentin ultrastructure.

OBJECTIVES: The aim of this study was to evaluate the effect of different irrigation protocols on the root dentin structure using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). MATERIALS AND METHODS: Thirty-nine lower bovine incisors were hemisected longitudinally and randomly divided into 13 groups (n = 3). After the root halves were reassembled, it was applied a specific irrigation protocol for each group, as following: G1, distilled water (control); G2, 0.9% saline; G3, saline + 17% EDTA; G4, saline + PUI; G5, saline + PUI + EDTA; G6 to G9 received the same protocol as above replacing 0.9% saline by 2.5% NaOCl; and G10 to G13 by 2% CHX. One-half of each sample was prepared and evaluated using SEM and the other one by TEM observations. RESULTS: TEM descriptive analysis showed modifications in dentin organic ultrastructure, characterized by the thinning of dentin collagen fibrils, caused by NaOCl, enhanced by EDTA and/or PUI. SEM analysis showed that NaOCl with PUI caused significantly larger erosion of the peritubular dentin than in all the other groups (P < 0.05), followed by NaOCl + EDTA and NaOCl + EDTA + PUI. CONCLUSIONS: NaOCl caused ultrastructural alterations in the dentin collagen, and enhanced by EDTA and/or PUI, promoted peritubular and intertubular erosion. CLINICAL RELEVANCE: The effect of irrigating solutions on dentin ultrastructure was still unclear. The acknowledgment about the kind of solution, concentrations, application time, and sequence of use was important to achieve the right sanitization without jeopardizing the dentin ultrastructure quality.

The effect of final irrigation on the penetrability of an epoxy resin-based sealer into dentinal tubules: a confocal microscopy study.

INTRODUCTION: The aim of this study was to compare the effect of QMix, BioPure MTAD, 17 % EDTA, and saline on the penetrability of a resin-based sealer into dentinal tubules using a confocal laser scanning microscope (CLSM) and to describe the cleaning of root canal walls by SEM. METHODS: Eighty distobuccal roots from upper molars were selected and randomly divided into four groups (n = 20) before root canal preparation according to the solution used in the final rinse protocol (FRP): QG (QMix), MG (BioPure MTAD), EG (17 % EDTA), and CG (control group: saline). Ten roots of each group were prepared for SEM, and images (×2000) from the canal walls were acquired. The remaining canals were filled with a single gutta-percha cone and AH Plus with 0.1 % Rhodamine B. The specimens were horizontally sectioned at 4 mm from the apex, and the slices were analyzed in CLSM (×10). Sealer penetration was analyzed with Adobe Photoshop software. RESULTS: QG and EG presented similar amounts of sealer penetration (P > .05). MG and CG presented the lowest penetrability values (P < .05). The best results for smear layer removal of the apical third of the root canal were achieved by the QG and EG groups when compared with MG and CG (P < .05). CONCLUSIONS: Seventeen percent EDTA and QMix promoted sealer penetration superior to that achieved by BioPure MTAD and saline. CLINICAL RELEVANCE: Despite studies have not confirmed the relationship between sealing ability of endodontic sealers and their penetration in dentinal tubules, sealer penetration assumes importance, since endodontic sealers, unlike gutta-percha, are able to penetrate in dentinal tubules, isthmus, and accessory canals, filling the root canal system.

The influence of different cements on the pull-out bond strength of fiber posts.

STATEMENT OF PROBLEM: Glass fiber posts are commonly used to provide adequate support and retention for the restoration of endodontically treated teeth, but their resistance to dislodgement depends on their adhesion to root dentin. PURPOSE: The purpose of this study was to assess the effect of cement type on the pull-out bond strength of fiber posts. MATERIAL AND METHODS: Seventy maxillary canines were endodontically treated and then divided into 7 groups according to the cement used for fiber post cementation as follows (n = 10): RelyX Unicem, BisCem, RelyX Luting 2, RelyX ARC, Panavia F, Enforce, and Allcem. The specimens were subjected to a pull-out bond strength test in a universal testing machine at a crosshead speed of 0.5 mm/min. The results, in newtons, were analyzed with 1-way ANOVA and the Tukey post hoc test (α = .05). RESULTS: RelyX Unicem (472.3 ± 8.9 N), BisCem (506.6 ± 9.2 N), RelyX ARC (498.0 ± 8.2 N), Panavia F (502.3 ± 7.0 N), and Allcem (470.0 ± 11.3 N) presented significantly higher bond strength than RelyX Luting 2 (241.8 ± 9.70 N) and Enforce (309.5 ± 6.3 N) cements (mean ± SD; P < .05). CONCLUSIONS: Except for Enforce, all resin cements produced pull-out bond strength values twice that of resin modified glass ionomer cement. However, all cements promoted adequate retention to fiber posts to withstand functional loads.

Increased Prevalence of Periapical Lesions in Osteoporosis Patients: A Systematic Review.

Assessing scientific literature about prevalence of periapical lesions in individuals with osteoporosis in comparison to those without osteoporosis. Systematic searches were conducted up to November 24th, 2023 in Cochrane Library, EMBASE, MEDLINE/PubMed, SCOPUS, Web of Science and Grey Literature Reports databases. Only observational studies were included. The ROBINS-E tool, a revised Cochrane instrument for assessing bias in nonrandomized exposure studies, was employed. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool was utilized to evaluate the certainty of the evidence. From 484 studies, three were included. One of them was categorized as having an exceptionally high risk of bias, while two were deemed to have certain concerns. Two studies reported that osteoporotic patients may have more chances to present a periapical lesion compared to non-osteoporotic patients. One study reported no differences between groups. The GRADE analysis indicated a markedly low level of certainty in the evidence. The present review indicates that osteoporotic patients may present more periapical lesions compared to non-osteoporotic patients. This statement should be cautiously interpreted and further well-designed studies are needed. (EEJ-2023-09-123).

Interfacial adaptation of NeoMTA Plus, BioRoot RCS and MTA in root-end cavities: A micro-CT study.

AIM: This study aimed to use the micro-computed tomography to evaluate the interfacial adaptation and the presence of gaps of NeoMTA Plus, BioRoot RCS, and MTA in the root-end cavities. METHODOLOGY: Thirty standardized bovine roots measuring 15 mm in length were selected. Chemical-mechanical preparation was performed up to instrument #80 and obturation with the cold lateral compaction technique with cement based on zinc oxide and eugenol. The roots were kept at 37°C for 7 days. Afterward, apicectomy of the apical 3 mm and a root-end filling cavity was performed at 3 mm depth. Micro-computed tomography (micro-CT) was performed to measure the volume of the retroactivity. The roots were divided by stratified randomization into three groups according to the retro-end filling material: NeoMTA Plus, BioRoot RCS, and MTA. A new micro-CT was performed to assess the presence of voids in the root-end filling material and between it and the canal wall. One-way ANOVA and Tukey tests were performed using the BioEstat 4.0 program. RESULTS: There was no difference in the initial volume values of the root-end cavities (p > .05). After the insertion of root-end filling materials, the most significant volumes of voids were observed in the NeoMTA Plus group (p < .05), with no difference for the BioRoot RCS and MTA Angelus groups (p > .05). CONCLUSION: Micro-computed tomography showed that MTA and BioRoot RCS have better interfacial adaptation and presented fewer number of gaps than NeoMTA Plus when used as root-end filling materials. RESEARCH HIGHLIGHTS: Micro-computed tomography evaluation of different root-end fillings materials.

A new method of adhesive system application improves the bond strength between fiber post and root dentin.

This study evaluated a new method of adhesive system application on the bond strength between fiber post and root dentin using two adhesive systems. The canals of sixty bovine incisors were prepared and obturated. The roots were divided into six groups (n=10) according to the adhesive system (Clearfil SE - CSE and Single Bond Universal - SBU) and the application strategy (microbrush - MB; rotary brush - RB; and ultrasonic tip - US). The glass fiber posts were cemented with resin cement (RelyX ARC). The roots were sectioned perpendicularly to their long axis, and three slices per root were obtained. Previously to the push-out test, confocal laser scanning microscopy (CLSM) was performed to illustrate the interfacial adaptation of the cement to the root canal walls. Failure patterns were analyzed with 40x magnification. Shapiro-Wilk indicated a normal distribution of the data. The bond strength values were compared using one-way ANOVA and Tukey's tests. Student's T test analyzed the differences between the adhesive systems within each third and protocol. A significance level of 5% was used. CSE with RB showed higher mean bond strength values compared to MB (conventional technique) (P < 0.05). US application resulted in intermediate bond strength values for CSE (P > 0.05). The application of SBU using RB generated higher mean bond strength values compared to MB and US (P < 0.05). Adhesive failures were predominant (65.5%). CSE and SBU application with the new rotary brush improved the bond strength of fiber posts to root dentin compared to the conventional strategy.

Three-rooted premolar analyzed by high-resolution and cone beam CT.

OBJECTIVES: The aim of this study was to analyze the variations in canal and root cross-sectional area in three-rooted maxillary premolars between high-resolution computed tomography (µCT) and cone beam computed tomography (CBCT). MATERIALS AND METHODS: Sixteen extracted maxillary premolars with three distinct roots and fully formed apices were scanned using µCT and CBCT. Photoshop CS software was used to measure root and canal cross-sectional areas at the most cervical and the most apical points of each root third in images obtained using the two tomographic computed (CT) techniques, and at 30 root sections equidistant from both root ends using µCT images. Canal and root areas were compared between each method using the Student t test for paired samples and 95 % confidence intervals. RESULTS: Images using µCT were sharper than those obtained using CBCT. There were statistically significant differences in mean area measurements of roots and canals between the µCT and CBCT techniques (P < 0.05). Root and canal areas had similar variations in cross-sectional µCT images and became proportionally smaller in a cervical to apical direction as the cementodentinal junction was approached, from where the area then increased apically. CONCLUSION: Although variation was similar in the roots and canals under study, CBCT produced poorer image details than µCT. CLINICAL RELEVANCE: Although CBCT is a strong diagnosis tool, it still needs improvement to provide accuracy in details of the root canal system, especially in cases with anatomical variations, such as the three-rooted maxillary premolars.