endodontics

The aim of this study was to assess gutta percha-induced TNF-alpha and IL-1 beta gene expression in the presence or absence of bacterial lipo-polysaccharide (LPS) on cultured human monocyte cells in vitro.

Human monocytes from THP-1 cell line were cultured. Standardized gutta percha segments were prepared and directly placed at the bottom of the culture wells. Cultured cells were exposed to the materials in G1 and G2 groups and then LPS was added only to G1. Positive control included the bacterial LPS without the gutta percha segments and the negative control contained the cells in culture medium only. TNF-alpha and IL1-beta gene expression was evaluated using RT-PCR technique. Data were statistically analyzed using Kruskal-Wallis and Bonferroni-adjusted post-hoc tests.

A statistically significant difference was noted between LPS-treated and un-treated groups regarding IL-1-beta and TNF-alpha gene expression (p < 0.05). In G2 (the gutta-percha without LPS), IL-1-beta, and TNF-alpha gene expression was signifi-cantly higher compared to the negative control group (p < 0.05). In G1 (gutta-percha with LPS), TNF-alpha and IL-1-beta gene expression was significantly higher than in the positive control group (p<0.05).

It was indicated that gutta-percha could induce the expression of pro-inflammatory cytokines TNF-alpha and IL-1-beta, with this effect being significantly magnified by LPS contamination.

Sinus tracts are routes of purulent drainage, which are supposed to be related to a specific source of infection. To the best of the authors’ knowledge, there have been no documented cases of multiple intra-oral sinus tracts arising from a non-vital maxillary molar. This observation highlights a unique clinical scenario that has not been previously reported in the literature.

A rare case with three intra-oral sinus tracts, all related to a non-vital, previously pulp-capped maxillary second molar is presented. After a two-visit root canal treatment, sinus tracts were closed and patient’s symptoms relieved. In such cases, a proper disinfection of the root canal system combined with an ideal obturation of the prepared canals would be required.

Necrotic maxillary molars might be associated with multiple sinus tracts.

Apical extrusion of debris has been associated with postoperative pain, flare-up and delayed periapical healing. Studies reported that reciprocating instrumentation was associated with more debris extrusion than rotary instrumentation. The purpose of this study was to compare the amount of apically extruded debris using single-file rotary and reciprocating instrumentation systems.

Sixty human maxillary premolar teeth were randomly assigned to three groups (n = 20): Reciproc R25 (VDW, 25, 0.08), Neoniti A1 (NEOLIX, 25, 0.08), Only One File (Denco, 25, 0.08). Canal instrumentation was done according to the manufacturers’ instructions. Measurements of debris were measured by Montgomery method. Brown-Forsythe test, robust and Games-Howell post hoc test were used for data analysis (α=0.05).

The results of this study showed that the highest amount of debris extruded is in the Reciproc file and the lowest is in Neoniti A1. There was a significant difference between the means of the three groups (P˂0.05). Games-Howell post-hoc test was showed that there is a significant difference in pair by pair comparison of groups (P˂0.05).

Based on this in vitro study, all systems have some apical debris extrusion; however, it seems that rotary single-file instrumentation system was better than reciprocating single-file instrumentation systems in terms of the amount of debris extrusion.

Paresthesia is described as a burning or prickling sensation or partial numbness caused by neurologic injury. The sensory loss may be the result of a reversible and/or irreversible nerve damage, and it can be caused by local or systemic factors. Local factors include traumatic injuries caused by impacted teeth, local injection, endodontic therapy, implant placement and exposure to toxic materials. This article reports a paresthesia by anesthetic injection. A 44-year-old man reported moderate pain during chewing and exposure to cold. Upon clinical examination, extension of the tooth fracture line was in the mesiodistal region of the mandibular left second premolar crown and was detected with 16× magnification of microscope. The diagnosis was cracked tooth syndrome, and root canal treatment was indicated. After the first appointment the patient reported altered sensation on left side of mandible, numbness and electric shock sensation, and therefore was diagnosed with mental nerve paresthesia. Diclofenac sodium, thiamine, cyanocobalamin, and pyridoxine were prescribed for 7 days as part of the treatment, and then root canal and restorative treatments were completed. Patient was scheduled for follow-up appointments after 1, 3, 6, and 8 months. After the first month, the feeling of paresthesia was still present and the patient was experiencing a painful “electric shock”. At the 8-month follow-up visit, the paresthesia had been resolved with return of normal sensation.

Restoring endodontically treated teeth (ETT) that exhibit cracks, enlarged roots, or weakened root walls is a frequent challenge in dental practice. The present study describes three cases in which contemporary restorative techniques were employed and suggests that applying Ribbond tape (RT) to ETT can improve fracture resistance and better prevent the propagation of cracks compared with traditional methods. Although extensive in vitro research has been conducted on fiber-reinforced composites, studies evaluating the clinical use and durability of fiber-reinforced composites to restore ETT are limited. This report strictly adhered to the case report (CARE) guidelines, and the treatments were initiated only after signed informed consents were obtained from the patients. Therefore, the old restorations were removed from the teeth that required intervention and composite resin core build-up was created, followed by endodontic treatments or retreatment. Subsequently, the endodontic accesses were reinforced with RT. The protective restorations were performed and bonded. The two-year follow-ups showed that the patients had complete remission of signs and symptoms, and they remain under monitoring. The study emphasizes the importance of internal reinforcement of ETT and strengthening weakened walls with a resin core build-up reinforced with fibers like RT. This approach enhances mechanical retention, inhibit fracture propagation, and establish a strong chemical bond between RT and resin. It is suggested to be a promising strategy for increasing the longevity and strength of the teeth, providing a conservative and effective alternative to traditional methods.

 The middle mesial canal (MMC) of mandibular molars is of particular interest in endodontics due to its complexity. This study investigated the association between MMC presence in first and second mandibular molars and the radiolucency in the furcation area using cone-beam computed tomography (CBCT) scans. 

 CBCT scans of 400 patients referred to the largest radiology center in Kerman City from January 1, 2022, to January 1, 2023, were examined. All CBCT scans were assessed for radiolucency in the furcation area and the presence of MMC. Variables, including age, gender, tooth number, and MMC presence were recorded. Chi-squared tests and logistic regression analyses were employed to compare MMC frequency and its impact on furcation radiolucency. 

 Of 201 examined teeth, 37 (18.4%) had MMC, and 23 (11.4%) exhibited furcation radiolucency. However, teeth with a mesial canal showed a higher prevalence of furcation lesions compared to those without (38% vs. 5.2%) (P<0.001). A significant association was observed between a mesial canal and furcation radiolucency, with odds of furcation radiolucency at 12.7 after controlling for age and gender (P<0.001). 

 A strong association exists between MMC presence in first and second mandibular molars and furcation radiolucency, unaffected by age and gender.

Vital pulp therapy (VPT) comprises a range of conservative treatment modalities aimed at preserving the vitality of the compromised dental pulp in primary and permanent teeth. This PubMed-based review comprehensively evaluates seven distinct VPT techniques; including their historical development, broad definitions, clinical protocols and treatment outcomes as evidenced by systematic reviews and meta-analyses. The VPT modalities covered in this review include stepwise excavation, indirect pulp capping, direct pulp capping, miniature pulpotomy, partial pulpotomy, full pulpotomy and partial pulpectomy. Stepwise excavation, as a minimally-invasive option, has demonstrated effectiveness in reducing the risk of pulp exposure, particularly in permanent teeth. Clinical outcomes of indirect and direct pulp capping are promising; specifically with the application of advanced calcium silicate cements. Miniature and partial pulpotomies emphasize the importance of precise definitions and standardised protocols due to their subtle differences. Full pulpotomy has emerged as a viable alternative to root canal treatment, achieving comparable success rates in managing irreversible pulpitis. While partial pulpectomy remains the most invasive approach, it has shown potential in managing complex cases, such as root resorption, through selective tissue preservation. Despite advancements in biomaterials and technique standardisation, challenges remain, including variability in clinical protocols, limited high-quality evidence, and the need for long-term studies to better evaluate anticipated outcomes. Nevertheless, emerging biotechnologies hold promise for enhancing the precision and predictability of VPT procedures in the future

Dens invaginatus is a developmental malformation that is caused by the invagination of the enamel organ into the internal region of the dental papilla before tissue calcification. The aim of the present report is to discuss a clinical case of endodontic treatment of tooth #12, using bioceramic sealer. The extraoral examination revealed atypical anatomy, while vitality and percussion tests were negative, palpation test was positive. Edema was observed in the adjacent gingival mucosa. Based on clinical and tomographic findings, the diagnosis was pulp necrosis with chronic periapical abscess and Oehlers’ type II dens invaginatus. In the first session, access surgery was performed with spherical drills with the aid of an operating microscope (OM) and an ultrasonic diamond tip. Four canals were located, and they were partially debrided and medicated. In the second session, odontometry and chemical-mechanical preparation with nickel-titanium instruments were performed. The irrigation solution was 2.5% sodium hypochlorite. The root canals were filled with calcium hydroxide paste and the chamber was temporarily sealed. During the third session, ultrasonic irrigation was applied for final washing and the root canals were filled with Bio-C sealer using the classic single-cone technique. At 6-month follow-up, the tooth was asymptomatic and the radiography revealed significant bone repair. It was concluded that tomography, operating microscope, ultrasonic irrigation, and materials with greater flow, such as bioceramic sealers, enhanced the clinical success of the clinical case.

Cold Ceramic (CC) is designed to meet the ideal criteria for root filling materials, offering effective sealing, biocompatibility, non-toxicity, dimensional stability, insolubility in tissue fluids, radiopacity, and ease of handling. It sets in the presence of moisture, making it suitable for various endodontic applications such as root-end filling, root perforation repair, apical barriers in teeth with open apices, and pulp capping. This study aims to evaluate cold ceramic’s clinical outcomes and applications as presented in case reports.

A comprehensive literature search was conducted to identify published case reports and case series on the clinical application of cold ceramics in endodontics from January 2000 to April 2024.  Databases searched included PubMed, MEDLINE, Scopus, Web of Science, Cochrane Library and Google Scholar. The search terms used were “cold ceramic,” “bio ceramic,” “endodontics,” “case report,” “clinical outcomes,” and “dental materials”. Articles in English and Persian were included. Patient demographics, cold ceramic brand, clinical procedures, outcomes, follow-up periods, and any complications were extracted. Quality assessment of the included case reports was performed using the CARE guidelines.

After removing duplicates and screening titles and abstracts, 7 case reports and 2 case series met the inclusion criteria. The reviewed case reports included 16 patients (9 female and 7 male) with a mean age of 29.25±1.2. Clinical outcomes were generally favorable, with high success rates and minimal complications reported.

All cases demonstrated radiographic and clinical healing and an absence of postoperative pain or infection during follow-up periods ranging from 3 months to 4 years. cold ceramics provide promising success rates and negligible complications in various clinical endodontic scenarios.

Invasive cervical resorption (ICR) is an aggressive pathological condition that can affect any permanent tooth. This process is characterized by replacement of the tooth structure with granulomatous fibrovascular or fibro-osseous tissue. Despite its asymptomatic nature, ICR can lead to tooth loss. This study reports a case of ICR in a 15-year -old boy with a history of dental trauma. The patient had a diagnosis of ICR in tooth #21. After considering the risks of an external surgical approach and exclusive endodontic treatment, intentional re-implantation combined with extraoral composite resin restoration and endodontic treatment was proposed. The procedure consisted of atraumatic tooth extraction, removal of granulomatous tissue, restoration of the cavity with composite resin, re-implantation of the tooth in the alveolus, and endodontic treatment. This approach resulted in satisfactory repair of the resorptive lesion observed in over 3 years of follow-up. This case highlights intentional re-implantation combined with appropriate endodontic treatment as a viable treatment option for ICR.

Pulp canal calcification (PCC) is common in patients with dentinogenesisimperfecta (DGI). We present endodontic management of multiple anterior and posterior teeth with PCCs in a patient with DGI type II using guided endodontics. A 26-year -old female patient was diagnosed with DGI type II. Clinical examination revealed palatal cusp fracture in tooth #13, microcracks in tooth #14, and a sinus tract in the maxillary right buccal vestibule related to tooth #13. Periapical radiographs revealed PCCs in all teeth, and periapical radiolucencies in several teeth. Due to difficult negotiation of canal orifices, guided endodontic approach was planned. Cone-beam computed tomography (CBCT) was requested and obtained. Intraoral scanning was performed, and CBCT and intraoral scanning data were superimposed. A template was designed and 3D printed. The root canal orifices were successfully negotiated and endodontic treatments were successfully accomplished. At the 1-year follow-up, the endodontically treated teeth were asymptomatic, and periapical lesions were healing.

This review evaluates the effectiveness of treatment modalities for immature teeth with pulp necrosis, focusing on calcium hydroxide (CH) and mineral trioxide aggregate (MTA) apexification, as well as regenerative endodontic treatments (RETs). Recent advancements and clinical outcomes are highlighted.

A comprehensive search of MEDLINE(PubMed), Embase, Cochrane Library, Scopus, and grey literature was conducted from inception to July 2024. Systematic reviews and meta-analyses (SR/MAs) assessing apexification and RET outcomes in immature teeth with pulp necrosis were included. Studies were selected based on predefined criteria, and data on study design, interventions, and outcomes were extracted. Methodological quality was evaluated using the AMSTAR-2 tool.

31 SR/MAs were included. The quality ranged from critically low to low, except one rated as high. MTA apexification was more effective than CH for faster apical barrier formation, though overall success rates were similar. MTA is preferred for its efficiency, but standardized protocols are needed, and tooth discoloration was noted as a potential complication. RET generally outperforms apexification in root maturation, with platelet concentrates like platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) showing promising results; PRP was associated with greater root length, while PRF showed superior apical healing. Variability in RET outcomes was noted due to the lack of standardized protocols. Comparative studies of RET versusapexification showed no significant differences in survival or overall success rates. RET often provides better apical closure and root development, though results vary. Both approaches are viable, but more research with standardized protocols and larger samples is needed to establish definitive clinical advantages.

MTA apexification and RET are viable alternatives to CH apexification, with RET showing greater potential for root development and apical healing. Future research should focus on developing standardized protocols and uniform RET guidelines, and evaluating long-term outcomes to establish efficacy and safety.

Statement of the Problem: 

Considering side effects of non-steroidal anti-inflammatory drugs (NSAIDs), herbal medicine including Urtica dioica might help reduce the pain.

The present study aimed to compare the effects of premedication with essential oil of Urtica dioica and ibuprofen on post-endodontic pain.

The present randomized clinical trial study was conducted on 60 patients with symptomatic irreversible pulpitis of mandibular first or second molars. The patients were randomly assigned to three groups (n=20) for premedication with 400 mg ibuprofen, 400 mg essential oil of Urtica dioica (Netonal; Barij, Iran), and placebo. The medications were taken 30 minutes prior to the procedure. The patients’ pain score was recorded before the intervention and treatment onset (Time1 or T1), after the intervention prior the treatment onset (10 minutes after anesthetic injection) (T2), upon completion of treatment (T3), and at 8 (T4), 12 (T5), and 24 hours after endodontic treatment (T6) using a visual analog scale (VAS) and Wong-Baker FACES Pain Rating Scale (WBS), and compared. Data were analyzed by Chi-square test, one-way and repeated measures analysis of variance (ANOVA), kruskal-wallis test, and LSD post-hoc test using IBM SPSS statistics version 21 with significance value of p< 0.05.

The pain score was not significantly different among the three groups at T1, T2 and T3 according to both scales (p> 0.05). On the other hand, significantly lower pain scores were recorded in ibuprofen and Urtica dioica groups at 8, 12, and 24 hours after treatment compared with the placebo group (p< 0.001). The pain score was not markedly different between the ibuprofen and Urtica dioica groups (p> 0.05).

It seems that analgesic effect of premedication with leaf extract of Urtica dioica is the same as ibuprofen. Further studies are warranted to find the optimal dosage of Urtica dioica for widespread use.

 The effectiveness of final root canal irrigants is crucial for successful conventional and regenerative endodontic treatments. This study aimed to systematically review the impact of final irrigants on dentin, disinfection, and regenerative potential in endodontic therapies.

 MEDLINE, Cochrane Library, and Web of Science databases were electronically searched for articles on final irrigants in conventional and regenerative endodontics, evaluating effects on dentin, smear layer, fracture resistance, stem cells, growth factors, and antimicrobial properties. The risk of bias was assessed using the Systematic Review Centre for Laboratory Animal Experimentation risk of bias tool.

 Overall, 25 eligible studies were included in this review after screening 2842 articles. Commonly assessed irrigants included ethylenediaminetetraacetic acid (EDTA) (21 studies), sodium hypochlorite (NaOCl; 12 studies), and citric acid (6 studies). EDTA could enhance growth factors but could weaken dentin. NaOCl affected dentin despite its antimicrobial benefits. Nanoparticles, chitosan, peracetic acid (PAA), and citric acid showed potential benefits. A meta-analysis was not performed due to methodological heterogeneity.

 In general, optimized irrigation strategies balancing disinfection, biocompatibility, and regenerative potential are necessary. More research is required to develop improved irrigation protocols.

 Apical periodontitis is one of the common dental diseases. Microorganisms are the main reasons for these lesions; irrigations are used to remove them, but because of limited penetration, the rinsing agents may not always kill the microorganisms. Laser irradiation is effective in canal disinfection. The goal of this study was to compare the effect of calcium hydroxide (Ca(OH)2) and diode laser on the improvement of apical periodontitis following root canal retreatment (RCR).

 Twenty-four teeth of 19 patients with periapical lesions which needed RCR were divided into two groups (Ca(OH)2 and Ca(OH)2+laser irradiation [LI]). In the first session, after gutta-percha removal, cleaning, and shaping, Ca(OH)2 was used for 10 days. In the second
session, in the Ca(OH)2+LI group, the irradiation utilizing a diode laser (using non-initiated 200- µm fiber, continuous wave (CW), power output of 1W) was done. The periapical radiographic healing was assessed before the retreatment and after 3-month and 6-month follow-ups by periapical index (PAI) Qrstavik. The quantitative data were analyzed (P<0.05).

 The initial periapical lesion score was 3.75 and 3.88 in the Ca(OH)2 and Ca(OH)2+LI
groups, respectively. In the Ca(OH)2 and Ca(OH)2+LI groups, 3 months after the RCR, the average periapical lesion score was 2.94 and 3.05, respectively. In the Ca(OH)2 and CA(OH)2+LI groups, 6 months after the RCR, the average periapical lesion score was 1.80 and 1.75, respectively. No significant differences were found at the 3 and 6 months between the experimental groups.

 The diode laser can reduce the periapical lesion, but there was no significant difference between CA(OH)2+LI and Ca(OH)2 at 3-month and 6-month follow-ups.

This study aimed to compare the effects of requirement-based and test-based formative assessment methods on pre-clinical endodontic competence and performance of dental students.

This interventional field study was conducted on dental students of Shahid Beheshti Dental School in the first and second semesters of 2021 academic year (third-year students), taking practical basic endodontics 1. After receiving theoretical instructions and practical demonstrations, the students in both groups were asked to perform root canal therapy for extracted maxillary anterior and mandibular/maxillary canine teeth as part of their requirement. Their errors were assessed and recorded by two calibratedinstructors. Next, group 1 students performed root canal therapy for mandibular incisors and premolars as their requirement and returned the treated teeth on a specific date every 3 weeks. Group 2 students did not have a specific requirement and only participated in an examination which included endodontic treatment of the same group of teeth treated by group 1 students at the same designated dates. The treated teeth were assessed by instructors for errors. A final examination was held at the end of the semester for both groups. The two groups were compared by independent t-test, ANCOVA, Pearson Chi-square, and Mann-Whitney tests (alpha=0.05).

No significant difference was found between the two groups in access cavity preparation, root canal instrumentation, or obturation (P>0.05).

Requirement-based and test-based formative assessment methods had similar effects on pre-clinical endodontic competence and performance of dental students

This case report highlights the successful management of a cystic apical lesion associated with root resorption through nonsurgical endodontic retreatment, utilizing calcium-enriched mixture (CEM) cement as an obturating biomaterial. A 35-year-old woman presented with mild discomfort in the mandibular right first molar (#46), with radiographic evidence of a well-defined radiolucent lesion at the apex of the mesial root. The tooth had a history of previous failed endodontic treatment with poor root canal obturation, indicating internal root resorption. Nonsurgical endodontic retreatment was performed, and the canals were filled/sealed with CEM cement. Follow-up radiographs showed a gradual reduction in the size of the cystic lesion. At 54 months, complete bone healing of the cystic apical lesion was evident. This case report provides clinical evidence supporting the potential efficacy of nonsurgical endodontic retreatment using CEM cement in managing certain cystic apical lesions, offering a promising alternative to traditional surgical enucleation, even in cases with inflammatory root resorption. Further research is needed to validate the long-term efficacy of this approach in larger patient populations.

Immediate care and accurate diagnosis are essential for treating dental trauma. This reportpresentsa7- year -old boy suffered a bicycle accident with direct trauma to the mouth and extrusive luxation of teeth #11 and #21. The emergency treatment was performed within the first hour. Clinical examinations showed that both teeth exhibited 3 mm extrusion fromcomparing their incisal edges to their neighboring teeth, had edematous gingiva, showed grade 3 mobility and were painful to percussion. Radiographic exams showed incomplete root formation, widened periodontal spaces along their entire lengths and absence of bone or root fractures. The treatment consisted of immediate repositioning and semi -rigid splinting. After 15 days, tooth #11 exhibited no clinical signorsymptom and tooth #21 was diagnosed with pulp necrosis, with an acute dentoalveolar abscess and intraoral edema. Immediate endodontic treatment was initiated (intracanal dressing with calcium hydroxide paste). At 30 days, another pulp sensibility test was performed on tooth #11, which had a negative response. In the same visit, the intracanal dressing of tooth #21 was replaced. The Ca(OH)2medication was replaced every 6 months until the formation of an apical barrier. The final dressing consisted of gutta-percha and Grossman’s sealer and was placed two and a half years after the first dressing appointment. The extrusive luxation resulted in two different sequelae: complete root obliteration in tooth #11 and anomalous root development after the formation of an apical barrier in tooth #21. The patient received orthodontic treatment after 6 years from the initial treatment with no negative outcome. After 18 years follow-up, both teeth were stabilized with no symptom or sign. It’s important to follow the evolution of every trauma case continuously because the sequelae can be unpredictable

Introduction:

This study used different irrigation techniques to compare the levels of apical bacterial extrusion during the preparation of root canals with a reciprocating instrument widely used in endodontics, the Reciproc files 25/0.08 and 40/0.06.

The irrigation techniques employed were conventional syringe irrigation and passive ultrasonic irrigation (PUI); the latter, with one or two activation cycles. Seventy extracted mandibular human premolars were contaminated with Enterococcus faecalisfor 5 days and were distributed into 6 experimental groups (n=10), and the remaining specimens were used as positive and negative control groups (n=5). Group 1: instrumentation performed with Reciproc 25/0.08 and conventional syringe irrigation; Group 2: instrumentation performed with Reciproc 25/0.08 along with PUI for one minute after instrumentation (PUI-1) ; and Group 3: instrumentation performed with Reciproc 25/0.08 along with PUI for one minute before and after instrumentation (PUI-2). Groups 4, 5 and 6 were instrumented with Reciproc 40/0.06, and irrigation was performed similar to the previous groups, in the aforementioned order. Each root canal was irrigated with saline solution. Extruded debris was collected in microtubes. The contents of the microtubes were homogenized, diluted, and spread on Brain Heart Infusion agar. After 48 hours, the number of colony-forming units was determined for each sample. For statistical analysis, the Kruskal-Wallis test followed by the Dunn’s tests were used (α=0.05).

The CFU/mL count indicated that the instrumentation with Reciproc 25/0.08 was associated with the highest bacterial extrusion, mainly when PUI was performed (P<0.05).

All the instrumentation techniques caused bacterial extrusion through the apical foramen; however, the largest file size of the Reciproc 40/0.06 groups was associated with less apical bacterial extrusion.

Ultrasonic vibration for metallic post removal seems to be a unanimous choice between endodontists and general practitioners for providing the best results and having the highest safety. This study compared the time required by ultrasonic vibration for removing metallic post (MP) when 1 or 2 ultrasonics devices are used.

One hundred and fifteen teeth with MPs from 105 patients, indicated for nonsurgical endodontic retreatment were divided into 2 groups according to the number of ultrasonic devices used (G1-1 device) and (G2-2 devices). In G1, the MP was worn with a transmetal bur, alongside the wear of the cement line (around 2 mm deep). Then, an ultrasonic tip attached to an ultrasonic unit, with a power of 100% was activated at the level of the post, with constant water spray at a level of 1 mm above the axial surface of the tooth. The position of the tip was changed between buccal and lingual surfaces every 10 seconds until the MP was removed. In G2 the same procedures were performed as described in G1, but two ultrasonic tips were activated simultaneously at buccal and lingual surfaces until the MP was removed. The vibration time necessary for removing each MP was recorded using a chronometer.

The mean time was 131.10±29.68 seconds (mean±standard error of the mean) for MP removal using one ultrasonic device, and 24.86±6.88 seconds for two devices. The time required for MP removal using two ultrasonic devices was significantly less than when using one ultrasonic device (P<0.001).

The technique with 2 ultrasonic devices proved to be more efficient than the one using only 1 ultrasonic device.