Acute Pulpitis Research Articles

The Lunar Cycle and Its Relationship to Dental Emergencies: Acute Pulpitis

The aim of this study is to investigate a possible relationship between the full moon/lunar cycle and acute irreversible pulpitis emergencies. Acute pulpitis patients treated at the Department of Endodontics over a 3-year period were reviewed. Each lunar phase (new moon, first quarter, full moon, and last quarter) was considered a 1-day period, and the number of acute pulpitis emergencies per lunar day was calculated. Of 8533 referrals, 688 were recorded on 105 lunar-phase days. There was no significant difference in the number of acute pulpitis cases among phases of the Moon; however, on average, there were 15% more acute pulpitis cases at full moon (P =1.09, χ2=6.06). The effect of the Moon on acute pulpitis remains unconfirmed.

Anti-inflammatory drugs prescription in the department of endodontics, university hospital centre of cocody, Abidjan

Inflammation is the body’s common defense and adjustment process from any tissue attack. Administering anti-inflammatory drug may help define inflammatory responses. In endodontics they are increasingly administered topically and/or systemically. The objective of this study was to assess anti-inflammatory drug prescription patterns in endodontics at the University Hospital Center (UHC) of Cocody Abidjan. A descriptive retrospective study was carried out, analyzing 100 medical records of patients who had been at the department of Endodontic between January 2015 and December 2017. Systemically and/or topically anti-inflammatory drugs had been prescribed in 71% of cases following initial treatment, particularly in cases of acute pulpitis (35.20%). Moreover, although the obturation apical limits were normal and regardless of the quality of the filling, these prescriptions were still given (45%), and Ibuprofen was the most prescribed anti-inflammatory (51.70%). Prescribing anti-inflammatory drugs in endodontics is essential for defining inflammatory phenomena. However, it must be proper and controlled at the University Hospital of Cocody, Abidjan.

Impact of COVID-19 on Dental Emergency Services in Cluj-Napoca Metropolitan Area: A Cross-Sectional Study.

This study aimed to assess dental care needs in Cluj region during the State of Emergency, declared due to the COVID-19 pandemic, compared to the same period of the year 2019. A descriptive retrospective analysis was conducted, which retrieved patients seeking emergency dental services at the Emergency Department of County General Hospital and “Iuliu Hațieganu” University of Medicine and Pharmacy, Cluj-Napoca, Romania, the only dental service available in April 2020. Recorded data cover the month of April 2020 and is compared with the same period of 2019. During April 2020, 724 patients received dental care, whereas only 160 patients were treated in April 2019 in the same facility. The number of patients with acute apical periodontitis, abscess, and acute pulpitis was significantly higher in 2020. The percentage of patients receiving sedative filling for the treatment of acute pulpitis in 2020 was significantly higher than in 2019, while the proportion of patients receiving pulpectomy was higher in 2019. The percentage of patients receiving endodontic drainage for the treatment of acute periapical periodontitis in 2020 was higher. This study demonstrates that the COVID-19 pandemic impacted the use of medical care services and could further impact the oral health and quality of life of patients.

Endodontic implications and innovative preventive strategies during novel COVID-19 pandemic requiring emergency endodontic treatment

Endodontics a specialty branch in dentistry frequently deals with endodontic emergencies and during this COVID-19 pandemic Emergency Root Canal Treatement (ERCT) is often required to manage acute pulpitis with or without space infections.

Osteoplastic material from demineralized of allocate in the treatment of primary and acute pulpitis in children

Relevance. Initial and acute forms of pulpitis are fairly common diseases and require urgent treatment. Existing methods of endodontic treatment do not have sufficient efficiency and the introduction of new methods and drugs is required to improve the effectiveness of the treatment.Purpose. Improving the effectiveness of treatment of initial and acute pulpitis of permanent teeth in children using allogeneic demineralized plastic material (CPM).Materials and methods. The surface structure of a demineralized bone graft (DCT) and an allogeneic composite plastic material (CPM) were studied by scanning electron microscopy (SEM Philips SEM 515) with an EDAX microanalysis prefix . In the clinic, CPM was used in 10 patients aged 9 to 15 years in the treatment of pulpitis of permanent teeth with unformed roots.Results. The morphological structure of alloplastic material is fine-pored , with pore sizes of 10-20 microns, uneven, with protrusions and depressions, sometimes with a pore size of up to 250 microns. Clinical laboratory and radiological methods of research in children in the long term up to 3 years have confirmed the effectiveness of CPM in the biological method of treatment of pulpitis in children. In 9 patients, a positive result was obtained with the preservation of pulp viability and the formation of dental roots.Conclusions. Allogeneic bone-plastic material, which has osteoplastic and antimicrobial properties in the treatment of pulpitis in children, allows to preserve the viability of the pulp and the possibility of full-fledged formation of tooth roots.

Evaluation of Post-operative Pain after Irrigation Using End-vented NaviTip Tips versus Vibringe Sonic Irrigating System in Teeth with Acute Pulpitis with Apical Periodontitis: A Randomized Clinical Trial

AIM: This clinical study was conducted to evaluate and compare the post-operative pain after the using of two different irrigating techniques: Vibringe sonic irrigating system with end-vented NaviTip and conventional needle with end-vented NaviTip immediate postoperatively and 4, 12, 24, 48, and 72 h and 7 days utilizing a numerical rating scale (NRS).
 METHODS: Thirty-eight patients with acute pulpitis with apical periodontitis were involved in this study. Root canals were prepared using NiTi ProTaper Universal rotary system then randomized into two equal groups according to the technique used for irrigation Group A, Vibringe sonic irrigating system with end-vented NaviTip and Group B, conventional syringe with end-vented NaviTip® irrigating tip. The needles of irrigation were penetrated 2 mm shorter than the working length. The trial design of this study is a parallel randomized controlled trial.
 RESULTS: All demographic data, clinical and radiographic findings, and modified NRS scores obtained from patients were statistically analyzed. Results showed that there was no statistically difference between the two groups regarding the demographic data, prevalence of pre-operative pain, after 4 h, 12 h, 24 h, and 48 h and 7 days, while in both groups, there was a statistically significant decrease in pain intensity preoperatively compared with all other time periods.
 CONCLUSION: There is no statistical significance difference between Vibringe sonic irrigating syringe with endvented needle and conventional syringe with end-vented NaviTip, while in both groups, there was a statistically significant decrease in pain intensity preoperatively compared with all other time periods.

Changes in Expressions of Bcl-2, Inflammatory Factors IL-1, IL-6 and IL-8 and Intercellular Adhesion Molecule-1 in Inflammatory Dental Pulp

Background: To investigate the expressional changes of intercellular adhesion molecule-1 (ICAM-1), B-cell lymphoma/leukemia-2 (Bcl-2) and inflammatory factors [interleukin-1 (IL-1), IL-6 and IL-8] in the inflammatory dental pulp. Methods: 70 patients from June 2017 to May 2018 were selected as the research objects. The levels of ICAM-1, Bcl-2, IL-1, IL-6, IL-8 and in the third molars were detected and compared between healthy people and patients with acute and chronic pulpitis. Results: We found weak positive result regarding Bcl-2 and ICAM-1 expressions in normal dental pulp, while positive signal was enhanced in chronic pulpitis, and strongly positive was found in acute pulpitis. The expressions of inflammatory factors IL-1, -6, -8 in normal dental pulp were significantly lower than those in dental pulp with acute and chronic inflammations (p < 0.05). The inflammatory factors levels in dental pulp with chronic inflammation were significantly decreased compared with those in dental pulp with acute inflammation (p < 0.05). Conclusion: Bcl-2 and ICAM-1 cause the occurrence of inflammatory dental pulp, along with the abnormal increase of IL-1, IL-6 and IL-8.

Oral Health Management of Children during the Epidemic Period of Coronavirus Disease 2019

Coronavirus disease 2019 (COVID-19) is becoming a major public health event affecting China and even the whole world. During the epidemic period of corona virus disease, appropriate oral health management and disease prevention of children is very important for children's oral and general health. In order to prevent the occurrence of cross-infection and epidemic spreading of COVID-19 during dental practice, the recommendations to parents include: not only training children to maintain hand hygiene at home, exercise appropriately, strengthen physical resistance, but also helping children develop good oral and diet habit such as effective brushing and flossing to avoid oral diseases and emergency. If non-emergency oral situation occur, parents could assist their child to take home based care such as rinsing to relieve the symptoms. When oral emergencies such as acute pulpitis, periapical periodontitis, dental trauma, oral and maxillofacial infections happen, parents and children should visit dental clinic in time with correct personal protection. During the epidemic period, children's oral emergencies should be treated in accordance with current guidelines and control of COVID-19.

Efficacy of the osteocentric method of intraseptal anesthesia in mandibular molars treatment with dental caries and irreversible pulpitis

In the literature, various methods for the mandibular molars anesthesia are known, including periodontal pains as an adjunct to nerve block. However, these methods do not provide for amendments in the case of partial destruction of the vertices of the cortical substance of the bone tissue of the mandible. Aim: to perform a clinical and functional research of the possibility of using the osteocentric method of intraseptal anesthesia in mandibular molars treatment with dental caries and irreversible pulpitis. Materials and methods. In total, 324 patients aged 32—65 years (mean age 48.5 years). In all cases was used 4% solution of articaine with epinephrine 1: 200,000 (Septanest, 40 mg + 5 μg of epinephrine per 1 ml, Septodont) and short 30G Septaject Evolution dental needles (0.30×9 mm) with a scalpel-like cut. To assess the effectiveness of the anesthesia was performed pulp electrical stimulation before the study, after 2, 5 and 10 minutes after injection with the IVN-01 “Pulptest-Pro” electronic pulp test device (“Cascade-FTO”, Russia). Results. The treatment of the tooth decay (213 cases) was started at 3 minutes after the injection. Of 127 teeth treated with endodontic methods, for 104 (81.9%) teeth the duration of anesthesia was sufficient for amputation and extirpation of the pulp. With the removal of 23 (18.1%) teeth for acute pulpitis, the final stage of pulp extirpation was painful. Conclusion. This method of anesthesia can be especially recommended for people with somatic pathology because of a minimal amount of local anesthetic (0.36 ml for a two-canal tooth) with epinephrine 1:200,000.

Trigeminal Schwannoma simulating orofacial pain: differential diagnosis and treatment. Case report

ABSTRACT BACKGROUND AND OBJECTIVES: Orofacial pain is a major diagnostic challenge for the most experienced clinicians. Due to the complexity regarding the trigeminal-cervical joint, orofacial pain with the same etiology may present different symptoms, and pain with similar symptomatology may have different causes. The objective of this study was to alert health professionals about the importance of differential diagnosis in the hypothesis of trigeminal neuralgia, where the inclusion of the dentist in the medical-hospital team is of paramount importance in establishing the correct diagnosis. CASE REPORT: Twenty-nine-year-old female patient complained of electric shock and pulsatile orofacial pain that covered the third division of the fifth cranial nerve on the right side. Magnetic resonance imaging revealed the presence of trigeminal Schwannoma, causing neuralgia due to its neural compressive nature. Two different neurosurgery departments suggested tumor resection. However, after the evaluation by a third neurosurgery department, in which a dentist, specialized in orofacial pain was part of the team, the complete evaluation established the final diagnosis of right lower first molar odontalgia, with irreversible acute pulpitis as the cause of the symptoms and the expansive lesion was only a radiological finding. CONCLUSION: Interdisciplinary evaluation among physicians and dental surgeons is necessary to obtain the correct diagnosis when considering the hypothesis of trigeminal neuralgia.

Preoperative Acetaminophen- Caffeine- Codeine Combination and Anaesthetic Success in Patients With Acute Pulpitis

Preoperative Acetaminophen- Caffeine- Codeine Combination and Anaesthetic Success in Patients With Acute Pulpitis

CEREBRAL OXIMETRY AS A NEUROMONITORING TECHNIQUE DURING ORAL SANATION IN CHILDREN UNDER GENERAL ANESTHESIA ON AN OUTPATIENT BASIS

The article presents the results of assessing cerebral metabolism in children during oral cavity sanitation under conditions of general anaesthesia on an outpatient basis. The procedure was performed by using a non-invasive technique of neuromonitoring, cerebral oximetry, aimed at detecting changes in the cerebral oxygen supply. The method of cerebral oximetry enables to diagnose reduced oxygen saturation of cerebral tissues in early stage that significantly cuts down the risk of pathological organic changes in the brain and, as a consequence, decreases the risk of functional postoperative changes. It is noteworthy that rSO2 is within the upper normal limit (74.41% ± 2.08). This is explained by the peculiarities of the circulatory system in children and vascular walls in particular (developed capillary network, elasticity, and vascular permeability), as well as by the characteristics of the structure of the brain and increased oxygen consumption by cerebral neurons, which are in the stage of active development. It is important to stress that this figure is within the upper normal limit due to ↓rSO2 by 9.4% at the preoperative stage that can be explained by the high stressing, which in most cases is associated with "cryptogenic" phobias. This is a reasonable premise for administering anxiolytics prior dental intervention under general anaesthesia in an outpatient setting to avoid sharp fluctuations in cerebral oxygen saturation. The specific weight of ↓rSO2 in the preoperative stage in group of children is ↓ rSO2 (67.21%) in 24 (17.4%) children (7.18% relative to the total indicator of the identical group and 9.67% relative to the general group), who were at the renewal treated due to acute conditions (acute pulpitis, exacerbation of chronic periodontitis, periostitis). The period between dental interventions in these children did not exceed 2 weeks. This fact causes the necessity to limit the period of recurrent dental interventions to not less than two weeks. According to the results of the study, it has been found out that dental care under general anaesthesia on an outpatient basis while maintaining spontaneous breathing has time limits. It is advisable to perform general anaesthesia for 30 ± 10 minutes in children aged 0-3 years, for 40 ± 15 min. in children aged 3-12 years, and 60 ± 15 min. in children aged 12-18 years. The choice of dental treatment modes should be based on the time and possibility of a second visit. The term of planned dental surgery under general anaesthesia in an outpatient setting while maintaining spontaneous breathing after acute respiratory diseases requires at least two week period. In order to prevent the risk of complications during the oral sanitation at an outpatient setting under general anaesthesia, a period of scheduled dental recurrent interventions should be preformed not earlier than in two weeks.

Morphological Changes in the Dental Pulp of Experimental Animals in the Treatment of Acute Partial Pulpitis using Modern Materials

Aim.To study the morphological changes in the tooth pulp of experimental animals when modelling acute partial pulpitis using calcium silicate modified with light-cured resin and calcium hydroxide.Materials and methods.An experimental model of acute partial pulpitis was applied including the formation of a cavity on the lingual surface of the tooth, which corresponded to advanced caries in terms of depth, followed by a slight perforation up to the tooth pulp with a sharp probe. This model of acute partial pulpitis was reproduced for 32 teeth in four sexually mature rams. The teeth were extracted together with the surrounding sockets 15, 30 and 90 days after the modelling of pulpitis, followed by their fi xation in 10% solution of neutral formalin. Decalcification was performed in 25% solution of Trilon B. The material was poured into celloidin; histological sections were stained with hematoxylin and eosin according to Masson’s trichrome procedure.Results.The histological examination of pulp from the main group (calcium silicate modified with light-cured resin) revealed the formation of a biological barrier from secondary dentin in the area of the cavity and perforation up to the pulp chamber on the 90th day after the experiment started. The tooth pulp revealed no signs of an inflammatory process. On the 90th day after the experiment started, no pronounced morphological changes in the main substance and dentinal tubules in the area of the cavity walls were noted in the coronal pulp of experimental animals from the comparison group (calcium hydroxide). A focal chronic inflammatory process was noted in the tooth pulp.Conclusion.It was established that the use of calcium silicate modified with light-cured resin in the experimentally created model of acute partial pulpitis was accompanied by the formation of a biological barrier and a well-developed zone of reparative dentin in the area of the cavity and perforation up to the pulp chamber, as compared to the group where calcium hydroxide was used. Thus, the study results confirmed the efficay of using calcium silicate modified with light-cured resin within the biological method for treating acute partial pulpitis, which shortens the functional recovery of tooth pulp.

Is calcium hydroxide more effective than formocresol or camphor phenol as intracanal disinfectants in acute pulpitis among deciduous teeth?

Data sources Cochrane Library, PubMed, Ovid, ScienceDirect, Wiley, China Biology Medicine (CBM), China National Knowledge Infrastructure (CNKI), Wan Fang and VIP Database for Chinese Technical Periodicals (VIP) databases were searched for articles dating from January 2000 to July 2018. Studies in languages other than English or Chinese were excluded.Study selection Randomised controlled trials comparing the clinical effectiveness of calcium hydroxide to formocresol or camphor phenol in acute pulpitis of deciduous teeth requiring root canal treatment were included. The primary outcome was clinical effectiveness while the secondary outcome was incidence of endodontic inter-appointment emergencies.Data extraction and synthesis Two authors independently screened titles and abstracts of all studies identified through the search and reviewed full articles against established inclusion/exclusion criteria. Any disagreements between the authors were resolved by consensus or by consulting relevant experts. Risk of bias assessment was carried out using the Cochrane collaboration tool. Clinical effectiveness and incidence of inter-appointment endodontic emergencies were expressed as odds ratio and 95% CI. Heterogeneity was assessed using Q-test and I2 measurement. Appropriate models were used for meta-analysis based on heterogeneity.Results A total of 16 randomised trials informed the meta-analysis. Clinical effectiveness of calcium hydroxide was compared to formocresol in 12 studies and pooled data indicate that calcium hydroxide was significantly better in terms of clinical effectiveness (OR = 3.37; 95% CI 2.54 to 4.48), and was associated with significantly decreased inter-appointment emergency visits (OR = 0.26; 95% CI 0.16 to 0.42) . Calcium hydroxide was compared to camphor phenol in seven studies and was shown to be significantly superior in its clinical effectiveness (OR = 5.50; 95% CI 3.36 to 8.98).Conclusions Limited available evidence suggest calcium hydroixide was superior to formocresol and camphor phenol as intracanal medicaments in the management of acute pulpitis in deciduous teeth.

Clinical and patient-reported outcomes of implants placed in autogenous bone grafts and implants placed in native bone: A case-control study with a follow-up of 5-16years.

To compare the radiographic marginal bone levels of implants placed in sites previously augmented with autogenous bone grafts and implants placed in native bone. Secondary outcomes included: implant survival, periodontal/peri-implant parameters as well as short- and long-term patient-reported outcome measures. The study was designed as a case-control study including 38 patients equally distributed into two groups (previously augmented with autogenous bone blocks [AB] and implants placed in native bone [NB]). In total, 67 implants were placed. Clinical, radiographic and patient-reported outcome measures (PROMs), and complication rates were assessed based on a chart review and at a follow-up examination (≧5years after implant placement). Nonparametric mixed models were applied for the comparison of the two groups because of the clustered data. The data were analyzed descriptively, and p-values were calculated using nonparametric mixed models to account for the clustered data. The mean follow-up time was 10.2years (range 6-13years; AB) and 8.3years (range 5-16years; NB). One implant was lost in group NB (97.5% survival rate) and none in group AB (100%). Following primary augmentation, six major complications (wound dehiscences, acute pulpitis, intra- and extraoral sensitivity disturbances) were observed at the donor sites. At time of implant placement, only minimal complications occurred and only in group NB. Median marginal bone levels at the follow-up were significantly higher in group NB (1.15; Q1: 0.50mm/Q3: 1.83mm) than in group AB (1.58; Q1: 1.01mm/Q3: 2.40mm; p=0.0411). Probing depth, bleeding on probing and recession values were similar in both groups. PROMs revealed high visual analog scale values (i.e., high satisfaction) for both procedures. Dental implants placed in sites augmented with autogenous bone or in native bone revealed healthy peri-implant tissues after 5-16years. Marginal bone levels were significantly higher for implant placed in native bone. Complications following primary augmentation encompassed every third patient but were mostly transient.

EFFICIENCY OF APPLICATION OF MODERN MATERIALS IN A BIOLOGICAL METHOD OF PULPITIS TREATMENT OF EXPERIMENTAL

This article is devoted to the morphological substantiation of the usage of the developed dental medical pads (DDMP) in comparison with modern materials - “Biodentin” (Septodont), “Calcesil” (VladMiVa) and “TheraCal” (Bisco) on an experimentally formed model of acute focal pulpitis in rats taken Vivarium from the FSBEI HE Kuban State Medical University of the Ministry of Health care of Russia. The quality assessment with the usage of the above stated materials and the developed dental medical pad has been carried out by means of histological examination of the tissues of dental pulp on 3rd, 7th and 30th day from the start of the study. The received results of the experimental study has indicated various histological changes in the studied materials during the treatment of acute focal pulpitis with a biological method.

Avaliação da prescrição de antimicrobianos para tratamento de urgência endodôntica

Introdução: O uso de medicamentos em Odontologia tem por finalidade cessar a dor e prevenir a instalação ou a disseminação do processo infeccioso e inflamatório do paciente. Objetivo: Avaliar a prescrição de antimicrobianos para os casos mais comuns de urgência endodôntica. Materiais e métodos: Trata-se de um estudo de corte transversal, com amostra constituida de 209 cirurgiões-dentistas atuantes na cidade de Vitória da Conquista. Utilizou-se um questionário que abordou o tratamento de urgência endodôntica e informações sobre o uso de medicamentos nesses casos. Os dados foram tabulados e analisados no IBM SPPP Statistics para Windows, e comparados pelo teste qui-quadrado e teste exato de Fisher. Resultados: A maior parte da amostra possui atividade profissional entre 5 e 10 anos. Destes, 49,3% responderam que para casos de pulpite aguda indicaria pulpectomia associada à medicação intracanal. A pulpectomia associada a analgésicos e antibióticos para casos de periodontite apical aguda seria indicada por 35,9%. Nos casos de tratamento de abcesso apical agudo, 70,8% indicariam drenagem e antibióticos. Ainda, 56% dos entrevistados responderam que o tratamento do canal radicular seria o mais indicado para dentes com lesão periapical. Conclusão: A prescrição de antimicrobianos por parte dos profissionais entrevistados diante de casos de urgências endodônticas foi elevada, ocorrendo

Tissue Engineering: An Analogous Platelet Rich Fibrin for Coronal Pulpotomy in Revival of Pulp Tissue Vitality in Adult Molar with Pulpitis, a Case Report

Aim: management of a clinical case with irreversible pulpitis for young adult molar with closed apices using analogous blood derivative PRF and evaluating the clinical and radiographic success for coronal pulpotomy. Summary: A 18 years old male patient reported to the screening clinic, was referred to endodontic clinic with acute pulpitis diagnosed in left first molar tooth. Deep occlusal caries involving pulp, with history of spontaneous lingering pain associated with sign and symptoms of pulpitis. Standard clinical care protocol was strictly implemented, rubber dam isolation was followed by coronal pulpotomy. Blood drawn from cuboidal vein. Platelet rich fibrin membrane placed over the remaining pulp and restored with MTA and finally with Glass ionomer cement. Follow-up results clinically and radio-graphically were encouraging and successful at day 1 to 24 months. No post-operative pain, the treated tooth responded to pulp sensibility test and radiographs revealed periapical healing. However, for standardization of the clinical procedure well designed research study is further needed.

Management of Separated Instruments in Apical Third of Extremely Curved Canals: A Case Report

This report describes the case of a 23 years old male patient who presented with the chief complaint of pain in mandibular right lower first molar tooth. Detailed clinical and radiographic examination revealed acute pulpitis in lower right second premolar and first molar teeth. During root canal instrumentation, a rotary instrument separated at the apical third of mesiobuccal canal. After careful assessment, it was decided to bypass the instrument and obturate the root canal space with warm vertical compaction using thermoplasticized gutta percha and resin based sealer materials. After considering the curvature of canal, thin root of tooth and location of broken instrument in the apical third of canal space, attempts of instrument removal were ruled out as a treatment option for the patient. Bypassing the broken instrument fragment with pre-curved hand files of small sizes was chosen as a predictable treatment option since it is not associated with removal of excessive remaining dentin from the roots of the teeth. Hence, teeth do not become weak and risk of post-operative root fracture is minimized. Due to successful bypassing and preparation of root canal space beyond broken instrument, canal was shaped, cleaned and disinfected adequately. Decision of instrument bypassing or removal should be taken with extreme care. Bypassing the instrument in apical third of root canal space with thin rooted teeth is the most conservative and practical approach, and objectives of adequate shaping and cleaning of canals can be achieved successfully without compromising remaining tooth structure.

Effects of different root canal preparation techniques on premolars endodontic interappointment pain

Objective To study the clinical effects of different methods on endodontic inter appointment pain(EIAP) happened to the patients after premolar root canal preparations. Methods 152 teeth from 134 patients with acute or chronic pulpitis or apical periodontitis were randomly divided into T group and K group, used TiLos mixed root canal preparation system with step-down technique and stainless steel K file with step-back technique respectively to prepare root canal.Afterwards, the incidence rates of EIAP were observed and recorded. Results The incidence rates of EIAP in T group and K group were 6.17% and 21.11%, respectively.There was statistically significant difference between the two groups (χ2=7.404, P<0.01). Conclusion TiLos mixed root canal preparation system with step-down technique to prepare root cancal can reduce the incidence rate of EIAP. Key words: Root canal preparation; Toothache; TiLos mixed root canal preparation system; Step-down technique; Step-back technique; Premolar