Assessing the Iatrogenic Contribution to Contamination During Root Canal Treatment

IntroductionAsepsis in endodontics aims to control all potential sources of infection. Inadvertent introduction of bacteria into the root canal system may occur when the aseptic chain is breached during treatment. Therefore, measures are taken to prevent such microbial access and establish an aseptic environment. This study aimed to assess potential bacterial contamination and the potential risk of iatrogenic introduction from 7 sites comprising surfaces, instruments, and files acquired during the treatment of 30 vital, pulpitic teeth.MethodsBacterial samples were collected from access burs, files, endodontic rulers, rubber dam surfaces, gloves, and instruments. Genomic DNA was extracted and quantified by quantitative polymerase chain reaction. Bacterial types were determined using next-generation sequencing.ResultsHigh frequencies of contamination and microbial numbers were encountered in all sample types examined.Thirty-eight percent of the initial files introduced into the root canal had significant levels of bacteria at the point of obturation, including endodontic pathogens. Around half of the rubber dam surfaces were contaminated with substantial bacterial loads at the time of obturation, and bacteria were also detected in 20%–30% of gloves, instruments, and rulers before obturation. Next-generation sequencing revealed the predominant oral or endodontic origin of these contaminants, with the following genera identified: Streptococcus, Rothia, Granulicatella, Cutibacterium, Corynebacterium, Peptostreptococcus, and Fusobacterium. Together, these findings highlight the potential risk of reintroducing endodontically relevant bacteria during treatment.ConclusionsGloves, rubber dams, instruments, and files acquire bacterial contamination during treatment at high frequencies and loads. This highlights the potential risk of iatrogenic contamination at the clinically vulnerable point of canal obturation. Measures to address these may improve clinical outcomes.     

Bacterial Invasion of Pulp Blood Vessels in Teeth with Symptomatic Irreversible Pulpitis

IntroductionThis study described the degenerative changes and infection patterns of the pulp tissue associated with symptomatic irreversible pulpitis.MethodsThe material consisted of 32 extracted teeth with untreated deep caries that were clinically and histologically diagnosed with irreversible pulpitis and were part of the histopathologic collection of 1 of the authors. The controls consisted of intact teeth with normal uninflamed pulps and teeth with reversible pulpitis. Teeth were processed for histopathologic and histobacteriologic analyses.ResultsAll teeth with irreversible pulpitis showed areas of severe acute inflammation, necrosis, microabscesses, and bacterial infection in the pulp chamber. These areas were surrounded by a chronic inflammatory infiltrate, and, at the distance, the pulp tissue was often uninflamed. Bacteria were also observed in the areas surrounding the necrotic foci, both as scattered cells through the extravascular space and at varying numbers within the blood vessel lumen. The number of bacteria and the density of the intravascular bacterial aggregations varied considerably. In one third of the cases, bacteria occurred in the lumen of venules in areas at a considerable distance from the necrotic focus in the coronal third of the root. No intravascular bacteria were noted in the middle and apical segments of the canal. No bacteria were found in the pulps of any of the control specimens.ConclusionsBacterial invasion and colonization of necrotic areas were observed in the pulp of all teeth with caries exposure and symptomatic irreversible pulpitis. Bacterial penetration of blood vessels occurred in all cases, suggesting that this may be an important mechanism of spread of bacterial infection through the pulp tissue in an endodontic infection.     

不同剂量阿替卡因对不可复性牙髓炎下牙槽神经阻滞麻醉效果的比较

目的:本研究对仅有刺激痛的早期不可复性牙髓炎的患者在下牙槽阻滞麻醉时,比较使用1.7 mL阿替卡因和3.4 mL阿替卡因的麻醉成功率的差异。方法:将76名患者随机分为两组,1.7 mL组和3.4 mL组(两组都为4%阿替卡因与1∶100000的肾上腺素),进行下牙槽阻滞麻醉。根管治疗过程中,使用Heft-Parker视觉模拟量表(VAS)记录患者的疼痛值。对数据进行T检验和卡方检验。结果:72名患者纳入了研究结果,两组的成功率都没有达到100%,组间有显著差异(P<0.001),3.4 mL组有较高的成功率74.4%,1.7 mL组成功率为27.8%。结论:在对下颌第一磨牙进行下牙槽阻滞时,提高阿替卡因的注射剂量可以显著提高麻醉的成功率,但也达不到100%的麻醉成功。     

Evaluating the Periapical Status of Teeth with Irreversible Pulpitis by Using Cone-beam Computed Tomography Scanning and Periapical Radiographs

Introduction

The purpose of this study was to compare the prevalence of apical periodontitis (AP) on individual roots of teeth with irreversible pulpitis viewed with periapical (PA) radiographs and cone-beam computed tomography (CBCT) scans.

Methods

PA radiographs and CBCT scans were taken of 138 teeth in 130 patients diagnosed with irreversible pulpitis (symptomatic and asymptomatic). Two calibrated examiners assessed the presence or absence of AP lesions by analyzing the PA and CBCT images. A consensus was reached in the event of any disagreement. The data were analyzed using the hypothesis test, and significance was set at P ≤ .05.

Results

Three hundred seven paired roots were assessed with both PA and CBCT images. A comparison of the 307 paired roots revealed that AP lesions were present in 10 (3.3%) and absent in 297 (96.7%) pairs of roots when assessed with PA radiography. When the same 307 sets of roots were assessed with CBCT scans, AP lesions were present in 42 (13.7%) and absent in 265 (86.3%) paired roots. The prevalence of AP lesions detected with CBCT was significantly higher in the symptomatic group compared with the asymptomatic group (P < .05). An additional 22 roots were identified with CBCT alone.

Conclusions

The present study highlights the advantages of using CBCT for detecting AP lesions, especially in teeth with symptomatic irreversible pulpitis.     

Comparison of ADAMTS Levels in Pulp Tissue Samples of Healthy and Symptomatic Irreversible Pulpitis Teeth

IntroductionThe aim of this study was to compare the levels of different A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS; ie, ADAMTS-1, -4, and -9]) related to the breakdown of the proteoglycans and tissue inhibitor of metalloproteinase 3 (TIMP-3) levels that inhibit ADAMTS in the extracellular matrix of healthy pulp and symptomatic irreversible pulpitis.MethodsPulp tissue samples diagnosed with healthy and symptomatic irreversible pulpitis were collected from 48 participants. Healthy and inflamed pulps were directly transferred to Eppendorf tubes (Labosel, Istanbul, Turkey) and stored at ?80°C (Nüve-DF490; Nüve, Ankara, Turkey) until further use. Routine root canal treatment procedures for the teeth were performed, after which the treatment process was completed. The levels of ADAMTS-1, -4, and -9 and TIMP-3 were measured in supernatants of human dental pulp tissue extracts using enzyme-linked immunosorbent assay kits (USCN, Wuhan, China). The independent sample t test and 1-way analysis of variance were used for parametric data, and the Kruskal-Wallis and Mann-Whitney U tests were used for nonparametric data.ResultsThere was a statistically significant difference between ADAMTS-1 and -9 and TIMP-3 levels of the healthy pulp and pulpitis groups (P < .05), but there was no significant difference for ADAMTS-4 levels (P > .05). It was found that the levels of ADAMTS-1 and -9 were higher in the pulpitis group compared with the healthy pulp group, whereas the TIMP-3 level decreased (P < .05).ConclusionsAs a result of this study, it was concluded that ADAMTS-1 and -9 and TIMP-3 might have a role in pulpal inflammation, whereas ADAMTS-4 was not related to pulpal inflammation.     

The Apical Root Canal System of Teeth with Posttreatment Apical Periodontitis: Correlating Microbiologic,Tomographic, and Histopathologic Findings

IntroductionThis study evaluated the microbiological conditions of the apical root canal system of teeth with posttreatment apical periodontitis and correlated them with observations from cone-beam computed tomographic (CBCT) imaging, micro–computed tomographic (micro-CT) imaging, and histopathology.MethodsRoot apices were obtained from 36 root canal–treated teeth subjected to periradicular surgery. CBCT examination was available before surgery. The apical root specimens were scanned in a micro-CT device and then cryopulverized. The powder was subjected to DNA extraction for real-time polymerase chain reaction quantification of total bacteria, Streptococcus species, members of the phylum Actinobacteria, and Enterococcus faecalis. Microbiological findings were evaluated for associations with CBCT, micro-CT, and histopathologic data. An association between lesion size and the proportion of unfilled apical canal system volume was also assessed.ResultsAll cryopulverized specimens were positive for total bacteria. Actinobacteria and streptococci occurred in 35 and 33 specimens, respectively, and were usually dominant in the community. Actinobacteria counts were 2.23 times higher in granulomas than in cysts. Streptococci were significantly more present in small lesion cases. E. faecalis was detected in only 7 samples, always as a dominant community member. The association of total bacteria, streptococci, and Actinobacteria counts with the unfilled canal volume was significant in the univariate analyses but not confirmed in the adjusted analyses. Large lesions were significantly associated with a higher volume of unfilled apical canals.ConclusionsBacterial infection occurred in all root apices, with high prevalence and dominance of Actinobacteria and streptococci. The volume of the unfilled apical canal system was significantly associated with the lesion size and possibly with bacterial counts. Findings illustrate the need to thoroughly disinfect and fill the apical root canal of infected teeth during endodontic therapy.     

Comprehensive Analysis of Differentially Expressed Genes in Clinically Diagnosed Irreversible Pulpitis by Multiplatform Data Integration Using a Robust Rank Aggregation Approach

IntroductionMolecular diagnosis may overcome the limitations of clinical and histologic diagnosis in pulpitis, thereby benefiting many treatment techniques, such as vital pulp therapies. In this study, integrated microarray data on pulpitis were used to obtain a list of normalized differentially expressed (DE) genes for analyzing the molecular mechanisms underlying pulpitis and identifying potential diagnostic biomarkers.MethodsA systematic search of public microarray and sequencing databases was performed to obtain expression data of pulpitis. Robust rank aggregation (RRA) was used to obtain DE gene lists (RRA_DEmRNAs and RRA_DElncRNAs) between inflamed pulp and normal samples. DE genes were evaluated by functional enrichment analyses, correlation analyses for inflammation-related RRA_DEmRNAs, and protein-protein interaction and competing endogenous RNA network construction. Quantitative real-time polymerase chain reaction validation was applied in snap-frozen pulp tissues.ResultsUsing the GSE77459 and GSE92681 data sets, 280 RRA_DEmRNAs and 90 RRA_DElncRNAs were identified. RRA_DEmRNAs were significantly enriched in inflammation-related biological processes and osteoclast differentiation and tumor necrosis factor, chemokine, and B-cell receptor signaling pathways. The molecular complex detection and cytoHubba methods identified 2 clusters and 10 hub genes in the protein-protein interaction network. The competing endogenous RNA network was composed of 2 long noncoding RNAs (ADAMTS9-AS2 and LINC00290), 2 microRNAs (hsa-miR-30a-5p and hsa-miR-128-3p), and 3 messenger RNAs (ABCA1, FBLN5, and SOCS3). The expression between most top inflammation-related RRA_DEmRNAs in pulpitis showed positive correlations. Quantitative real-time polymerase chain reacation validated the expression trends of selected genes, including ITGAX, TREM1, CD86, FCGR2A, ADAMTS9-AS2, LINC00290, hsa-miR-30a-5p, hsa-miR-128-3p, RASGRP3, IL3RA, CCDC178, CRISPLD1, LINC01857, AC007991.2, ARHGEF26-AS1, and AL021408.1.ConclusionsThe identified biomarkers provide insight into the pathology and may aid in the molecular diagnosis of pulpitis.     

Residual Bacteriome after Chemomechanical Preparation of Root Canals in Primary and Secondary Infections

IntroductionSecondary infections may be linked to the presence of residual microorganisms within dental root canals. The purpose of this study was to investigate the bacterial composition of primary and secondary root canal infections before and after chemomechanical treatment.MethodsSamples were collected before chemomechanical preparation (S1) and before obturation (S2) from 19 subjects (10 primary and 9 secondary infections). DNA was extracted, and the V3/V4 region of the 16S ribosomal RNA gene was amplified using the 347 F/803R primers and paired-end sequenced using the MiSeq (Illumina, San Diego, CA) instrument.ResultsSequencing analysis yielded partial 16S ribosomal RNA gene sequences that were taxonomically classified into 10 phyla and 143 genera. The most prevalent phyla in the S1 and S2 samples were Firmicutes and Bacteroides; however, when comparing between sample groups, Proteobacteria seem to have been enriched in secondary infections. The dominant genera in the primary S1 samples were Bacillus, Streptococcus, and Prevotella, whereas Bacillus, Streptococcus, and Selenomonas dominated the secondary infection S1 samples. Bacillus and Marinilactibacillus were the most dominant genera in the primary and secondary S2 samples. The mean number of operational taxonomic units per sample was 32,656 (±12,124 SD) and 37,113 (±16,994 SD) in the S1 and S2 samples, respectively. Alpha and beta diversities presented the same pattern within samples from both groups.ConclusionsGreat interindividual variations in the bacterial composition of the root canal biofilms were observed. There was no difference in the bacterial composition before and after treatment, although some genera survived and seem to be part of a residual microbiome. Our findings revealed a high diversity of the bacterial communities present in root canal infections after chemomechanical treatment, although the majority of the taxa detected were in low abundance.     

Intraoral Somatosensory Alterations Impact Pulp Sensibility Testing in Patients with Symptomatic Irreversible Pulpitis

IntroductionThis case-control study aimed to compare trigeminal somatosensory sensitivity between patients with a clinical diagnosis of symptomatic irreversible pulpitis (n = 33) and healthy participants (n = 33) and to evaluate the impact of somatosensory stratification of symptomatic irreversible pulpitis on pulp sensibility testing.MethodsA standardized battery of qualitative sensory assessment measured intra- and extraoral sensitivity to touch, cold, and pinprick stimuli. Dental pain intensity (0–100, numeric rating scale) and duration (seconds) evoked by cold stimuli (refrigerant spray) were applied to, respectively, the nonaffected and affected tooth (cases) and the upper right and left premolars (controls); z score transformation, analysis of variance (ANOVA), and chi-square tests were applied to the data (P = .050).ResultsPatients with irreversible pulpitis reported intraoral hypersensitivity more frequently than healthy participants (58% and 33%, respectively; P < .05). In addition, patients with irreversible pulpitis reported higher z scores of pain intensity (ANOVA main effects, F = 37.10, P < .05, partial η² = 0.37) and duration (ANOVA main effects F = 23.3, P < .05, partial η² = 0.27) after the pulp sensibility test compared with healthy participants. Nevertheless, subgroup analysis taking into account the presence of intraoral hypersensitivity indicated that the pain lingered most for patients with symptomatic irreversible pulpitis who also presented intraoral hypersensitivity (Tukey test, P < .05) but with no differences between patients with irreversible pulpitis without intraoral hypersensitivity and healthy participants (Tukey test, P > .05).ConclusionsQualST is able to detect intraoral alterations in patients with symptomatic irreversible pulpitis that seem useful to stratify the patients into distinct subgroups. Therefore, somatosensory assessment of the adjacent tissues may provide diagnostic fine-tuning of dental pulp diseases.     

Combination of Nonsurgical Endodontic and Vital Pulp Therapy for Management of Mature Permanent Mandibular Molar Teeth with Symptomatic Irreversible Pulpitis and Apical Periodontitis

IntroductionThis prospective study evaluated the outcome of a combination of nonsurgical endodontic (NSET) and vital pulp therapy (VPT) for the management of mature permanent mandibular molar teeth with symptomatic irreversible pulpitis (SIP) and apical periodontitis (AP).MethodsInstitutional ethical clearance was obtained. Mandibular molar teeth (N = 60) with a definitive diagnosis of SIP and AP with a radiographic periapical index score (PAI) of ≥3 in either 1 of the roots (mesial or distal) were included. Block randomization was used for allocation. In the NSET group (n = 30), single-visit NSET was performed using a standardized operating protocol. In the NSET-VPT group (n = 30), subsequent to full pulpotomy, at the root orifice where a vital pulp was observed (as determined by the arrest of pulpal bleed upon application of a 2.5% sodium hypochlorite pressure pack), a mineral trioxide aggregate radicular barrier was placed, and it was covered with light-cured resin-modified glass ionomer cement. NSET was performed in the root exhibiting a PAI score ≥3. The tooth was permanently restored. Postoperative pain was assessed at 24, 48, and 72 hours. Teeth were followed up clinically and radiographically at 12 months. The presence/absence of symptoms and the change in PAI scores were noted. The data were statistically analyzed.ResultsThe success rate was 90% in the NSET group and 93.3% in the NSET-VPT group. According to an intergroup comparison between the proportion of teeth healed and nonhealed (radiographic), there was no significant difference (P > .05).ConclusionsThe combination of NSET and VPT is a viable biologically based minimally invasive treatment option for multirooted mandibular teeth with SIP and AP.     

Evaluation of Secondary Thermal Hyperalgesia Resulting from Pulpal Inflammation in Patients with Symptomatic Irreversible Pulpitis

IntroductionInflammation can lead to hyperalgesia and allodynia by activation or sensitization of peripheral and central nervous system neurons. This study aimed to assess the occurrence of secondary thermal hyperalgesia in patients with symptomatic irreversible pulpitis (SIP).MethodsThe cold sensitivity test (visual analog scale) was performed for the tooth with SIP, its adjacent sound tooth, the same sound tooth in the opposite jaw, and the contralateral sound tooth in the opposite quadrant of the same jaw. Next, the tooth with SIP underwent root canal treatment, and 3 weeks later, after complete elimination of pain, the teeth underwent cold sensitivity testing again.ResultsA total of 64 patients, including 41 women and 23 men 18–65 years old, were evaluated in this study. The response to the cold sensitivity test significantly decreased in the tooth with SIP (P < .001), its adjacent sound tooth (P < .001), and the same sound tooth in the opposite jaw (P = .004) but not in the contralateral sound tooth in the opposite quadrant of the same jaw (P = .45) after endodontic treatment. No significant difference was noted between men and women in the groups (P > .05).ConclusionsHypersensitivity to cold test due to pulpal inflammation can also result in exaggerated response of the adjacent sound tooth and the same tooth in the opposite jaw to cold sensitivity test; these observations can be explained by the central and peripheral sensitization mechanisms.     

The Effect of Submucosal Injection of Corticosteroids on Pain Perception and Quality of Life after Root Canal Treatment of Teeth with Irreversible Pulpitis: A Randomized Clinical Trial

Introduction

The aim of the present investigation was to study the effect of local infiltration of corticosteroids on postoperative pain and quality of life (QOL) in teeth with irreversible pulpitis after 1-visit endodontic treatment.

The Effect of Cryotherapy Application on the Success Rate of Inferior Alveolar Nerve Block in Patients with Symptomatic Irreversible Pulpitis

IntroductionThis randomized clinical trial assessed the effect of preoperative intraoral cryotherapy application on the success rate of inferior alveolar nerve blocks (IANBs) in patients with symptomatic irreversible pulpitis (SIP).MethodsOne hundred four patients with SIP were randomly distributed into 2 groups: control and cryotherapy groups. In the control group, patients received an IANB injection with 2% lidocaine. In the cryotherapy group, intraoral cryotherapy application was performed for 5 minutes after the IANB. Endodontic therapy was then conducted 15 minutes after the IANB injection. If the patients reported moderate or severe pain during the procedure, the IANB was defined as “unsuccessful,” and a supplementary injection was administered.ResultsAll patients reported profound lip numbness. The overall success rate for the IANBs was 43.3%. In the cryotherapy group, the success rate of the IANBs was 55.8%, whereas in the control group it was 30.8% (P < .05).ConclusionsIntraoral cryotherapy application increased the success rate of IANBs in mandibular molar teeth with SIP. However, supplemental anesthesia techniques may still be required to provide profound pulpal anesthesia in many cases.     

In Vivo Evaluation of Effect of Preoperative Ibuprofen on Proinflammatory Mediators in Irreversible Pulpitis Cases

IntroductionPreoperative administration of nonsteroidal anti-inflammatory drugs has been suggested as a method for increasing the efficacy of local anesthetics and decreasing postoperative pain in symptomatic irreversible pulpitis cases. However, the effects of ibuprofen at the molecular level are still unknown. Hence, the purpose of this study was to compare the levels of proinflammatory mediators in the dental pulp of teeth with irreversible pulpitis in patients who medicated with preoperative ibuprofen versus those who did not.MethodsThirty-four patients undergoing conventional endodontic therapy for teeth with irreversible pulpitis were selected and randomly assigned into either the ibuprofen or nonibuprofen group. Four patients undergoing endodontic therapy for prosthodontic reasons served as controls. Patients in the ibuprofen group were instructed to take 600 mg ibuprofen 1 hour before treatment, whereas patients in the nonibuprofen and control groups were asked to avoid analgesics before treatment. Blood samples obtained from the pulp upon access were tested for levels of prostaglandin E2, tumor necrosis efactor alpha, interleukin (IL)-6, IL-1β, and interferon gamma using high-sensitivity enzyme-linked immunosorbent assay. Postoperative pain levels were recorded for the groups. Data for the cytokine levels and postoperative pain were analyzed using statistical analysis.ResultsThere was a significant decrease in the levels of prostaglandin E2, tumor necrosis factor alpha, IL-6, and interferon gamma in the ibuprofen group compared with the nonibuprofen group. No significant differences were noted in the postoperative pain levels between these groups.ConclusionsThe data showed that preoperative ibuprofen significantly decreased the levels of most proinflammatory cytokines in the dental pulp, which could possibly help with anesthesia in irreversible cases.     

Clinical and Molecular Microbiological Evaluation of Regenerative Endodontic Procedures in Immature Permanent Teeth

IntroductionThis study evaluated the bacterial levels after regenerative endodontic procedures and their correlation with the treatment outcome using molecular microbiology methods.MethodsRoot canal samples of 15 necrotic immature teeth were analyzed by quantitative polymerase chain reaction. Bacteria were counted before treatment (S1), after irrigation with 6% sodium hypochlorite (S2), and after intracanal dressing (S3) using either triple antibiotic paste (n = 7) or calcium hydroxide with chlorhexidine (n = 8). The Wilcoxon test for related samples and the Mann-Whitney test were used for statistical analysis (P < .05). After a follow-up period of 12–48 months, clinical and radiographic findings were correlated with microbiological data using a linear regression model (P < .05).ResultsAll S1 and S2 samples were positive for bacteria, but the number of positive S3 samples decreased to 53.3% (P = .001). Overall, there was a significant reduction of bacterial levels after each treatment step (S1–S2, P = .001; S2–S3, P = .02). In the triple antibiotic paste and chlorhexidine groups, 57.1% and 50% of S3 samples were positive with median numbers of 6.97 × 10³ and 3.59 × 10⁴ bacterial cells, respectively. No significant differences were found between the groups. Periapical healing occurred in all cases despite the presence of low levels of residual bacteria. However, the latter had a negative impact on the thickness of dentinal walls (R² = 0.0043).ConclusionsAlthough the bacterial levels were drastically reduced after the regenerative endodontic procedures, the residual bacteria influenced the thickness of the dentinal walls.     

The Effect of the Anatomic Variables on the Success Rate of Anesthesia in Maxillary Molars with Irreversible Pulpitis

IntroductionObtaining anesthesia of teeth with irreversible pulpitis is 1 of the most challenging issues in endodontic practice. The aim of this study was to evaluate the effect of anatomic variables on the success rate of anesthesia in maxillary molars with irreversible pulpitis.MethodsPatients who had maxillary molars with irreversible pulpitis and who had already had a cone-beam computed tomographic (CBCT) scan performed were included in this study. After infiltration injection of an anesthetic solution, the success rate of anesthesia was recorded by asking the patients to rate their pain during access cavity preparation and root canal instrumentation as well as their need for a supplementary injection during the treatment. The distance of the palatal root to the buccal cortical plate was calculated using the Romexis Viewer (Planmeca, Helsinki, Finland) measuring tools in both the axial and coronal views. Data were analyzed by chi-square and t tests as well as receiver operating characteristic curve analysis.ResultsForty-seven maxillary first and second molar teeth were eligible to be included in this study. The overall success rate of anesthesia was 63.80%. The palatal roots that had their apex located more than 12.34 mm from the buccal cortical plate in the axial view, and 12.46 mm in the coronal view had a higher chance of anesthesia failure compared with the teeth with smaller distances. The presence of the maxillary sinus between the cortical plate and roots had no significant impact on the efficacy of anesthesia (P > .05).ConclusionsThe potential of anesthesia failure during the treatment of irreversible pulpitis in maxillary molars with a divergent palatal root is significantly higher than in teeth with shorter distances from the palatal root apex to the buccal cortical plate. If a patient already had a CBCT scan done for other reasons or the CBCT is available in his or her records, a dental practitioner can use it to predict anesthesia success for maxillary molars with irreversible pulpitis.     

口腔医学生临床前离体牙及人工根管根管治疗教学研究

目的：通过离体牙、人工根管培养实习医生了解并掌握根管治疗的标准程序和方法。方法：选择正畸患者拔除离体牙36颗、牙髓病及牙周病拔除离体牙42颗,人工根管4颗,分组采用常规改良逐步后退法、冠向逐步深入法进行根管处理、预备及充填,观察实习医生根管治疗掌握情况及模拟治疗效果。结果：离体牙采用改良逐步后退法时,前牙根管治疗成功率〉前磨牙〉磨牙（P〈0.05）;离体牙磨牙组中,采用冠向逐步深入法成功率高于逐步后退法（P〈0.01）。结论：采用人工根管可以直观的辅助实习医生体会弯曲根管的治疗,结合离体牙进行根管治疗训练可以提高加深实习医生对根管解剖结构、不同根管治疗方法的了解,对于实习医生临床前培养有明显效果。     

Efficacy of 6% Sodium Hypochlorite on Infectious Content of Teeth with Symptomatic Irreversible Pulpitis

IntroductionThe objective of this study was to monitor the effects of chemomechanical preparation (CMP) performed with 6% sodium hypochlorite and calcium hydroxide–based intracanal medication (ICM) on the levels and diversity of bacteria, endotoxins (lipopolysaccharides [LPS]), and lipoteichoic acid (LTA) in root canals of teeth with symptomatic irreversible pulpitis.MethodsSamples were collected from 10 teeth with symptomatic irreversible pulpitis before CMP (S1), after CMP (S2), and after ICM (S3). The levels of bacteria, LPS, and LTA were assessed by using checkerboard DNA-DNA hybridization, LAL Pyrogent 5000, and enzyme-linked immunosorbent assay, respectively. Wilcoxon test, repeated-measures analysis of variance, and Tukey post hoc test were used for statistical analysis at a significance level of 5%.ResultsForty species were detected at S1. Two species were eliminated after CMP and 5 after ICM. Resistant and pain-related species were detected in the root canals. Higher levels of culturable bacteria were detected at S1. However, CMP and ICM effectively reduced the microbial load in the root canals. Higher levels of LPS and LTA were detected at S1. CMP was effective in reducing both LPS and LTA (P < .05). ICM produced additional reduction in the levels of LPS (P > .05) and LTA (P < .05).ConclusionsChemomechanical preparation using 6% sodium hypochlorite and calcium hydroxide–based intracanal medication were effective in reducing the levels of bacteria, LPS, and LTA in teeth with vital pulp and irreversibly inflamed pulp.     

Effect of a Combination of Nitrous Oxide and Intraligamentary Injection on the Success of the Inferior Alveolar Nerve Block in Patients with Symptomatic Irreversible Pulpitis

IntroductionThe purpose of this prospective study was to determine the effect of a combination of nitrous oxide/oxygen and 1 set of supplemental intraligamentary/periodontal ligament (PDL) injections followed by a second set of PDL injections on anesthetic success in patients with symptomatic irreversible pulpitis (SIP).MethodsNinety-four patients with a mandibular posterior tooth diagnosed with SIP received nitrous oxide/oxygen and an inferior alveolar nerve block (IANB) with 2% lidocaine with 1:100,000 epinephrine. Patients rated the pain of PDL injections and endodontic access on a visual analog scale. If moderate to severe pain was felt during treatment, the operator administered 1 set of supplemental PDL injections with 4% articaine with 1:100,000 epinephrine. If moderate to severe pain was felt again during treatment, the operator administered a second set of supplemental PDL injections. Anesthetic success was defined as having no to mild pain during endodontic treatment.ResultsThe success of the IANB with nitrous oxide was 44% (95% confidence interval [CI], 34%–54%). The overall anesthetic success rate (IANB with PDL injections) was increased from 69% (95% CI, 60%–78%) with 1 set of PDL injections to 80% (95% CI, 72%–88%) with a second set of PDL injections.ConclusionsAlthough the second set of PDL injections increased anesthetic success, it was not sufficient to ensure complete pulpal anesthesia.