Incidence of Middle Mesial Canals in Mandibular Molars during Root Canal Treatment and Nonsurgical Retreatment

INTRODUCTION

Large-scale clinical studies on the incidence of middle mesial canals (MMCs) in nonsurgical root canal treatment (RCT) and retreatment of mandibular molars are lacking. The primary aim of this observational study was to determine the incidence of MMCs in mandibular first and second molars that received RCT or nonsurgical retreatment (NSRetx). The secondary aim was to determine factors associated with incidence of MMCs.

METHODS

Included were 3018 mandibular molars that received RCT (n = 1624) or NSRetx (n = 1394) by 3 endodontists in a private practice. Demographic and procedural data were collected. Bivariate and multivariable (Poisson regression model) analyses were performed.

RESULTS

Incidence of MMCs was 8.8% (n = 267). Although the bivariate analysis showed that NSRetx was significantly associated with incidence of MMCs, this association did not reach the threshold for statistical significance after controlling for all covariates (P = .07). Multivariable analysis on the entire cohort showed that incidence of MMCs was significantly associated with younger age (risk ratio [RR] = 1.62; 95% confidence interval [CI], 1.28-2.06), male gender (RR = 1.48; 95% CI, 1.18-1.85), preoperative cone-beam computed tomography (CBCT) (RR = 1.48; 95% CI, 1.17-1.89), and first molar (RR = 2.30; 95% CI:1.74-3.05). Subgroup multivariable analyses revealed that incidence of MMCs was associated with male gender only in the RCT group (RR = 2.26; 95% CI, 1.55-3.30) but not in the NSRetx group (RR = 1.11; 95% CI, 0.82, 1.50); and with preoperative CBCT only in the NSRetx group (RR = 1.78; 95% CI, 1.28, 2.50) but not in the RCT group (RR = 1.10; 95% CI, 0.71, 1.69). Associations with younger age and first molar remained unchanged.

CONCLUSIONS

Overall incidence of MMCs was 8.8%. Incidence of MMCs was significantly higher in younger patients and in mandibular first molars but was not associated with the type of treatment.

Surface plasmon resonance biosensors for early troponin detection

Acute myocardial infarction (AMI) is one of the life-threatening causes that decrease blood flow to the heart, leading to increased mortality and related complications. Recently, the measure of blood concentration of cardiac biomarkers has been suggested to overcome the limitations of electrocardiography (ECG) analyses for early diagnosis of this disease. Troponins, especially cardiac troponin I and cardiac troponin T, with high sensitivity and specificity, are considered the gold standards in myocardial diagnosis. Recently, the use of new biosensors such as surface plasmon resonance (SPR) for early detection of these biomarkers has been greatly appreciated. Due to the rapid, sensitive, real-time, and label-free detection of SPR-based biosensors, they can be applied for selective and nonspecific absorption that is intended to be used as an in situ cardiac biosensor. Here, we exclusively discussed the updated developments of these valuable predictors for the possible occurrence of AMI detected by SPR.

Artificial Intelligence in Endodontic Education

AIMS

The future dental and endodontic education must adapt to the current digitalized healthcare system in a hyper-connected world. The purpose of this scoping review was to investigate the ways an endodontic education curriculum could benefit from the implementation of artificial intelligence (AI) and overcome the limitations of this technology in the delivery of healthcare to patients.

METHODS

An electronic search was carried out up to December 2023 using MEDLINE, Web of Science, Cochrane Library, and a manual search of reference literature. Grey literature, ongoing clinical trials were also searched using ClinicalTrials.gov.

RESULTS

The search identified 251 records, of which 35 were deemed relevant to artificial intelligence (AI) and Endodontic education. Areas in which AI might aid students with their didactic and clinical endodontic education were identified as follows: 1) radiographic interpretation; 2) differential diagnosis; 3) treatment planning and decision-making; 4) case difficulty assessment; 5) preclinical training; 6) advanced clinical simulation and case-based training, 7) real-time clinical guidance; 8) autonomous systems and robotics; 9) progress evaluation and personalized education; 10) calibration and standardization.

CONCLUSIONS

AI in endodontic education will support clinical and didactic teaching through individualized feedback; enhanced, augmented, and virtually generated training aids; automated detection and diagnosis; treatment planning and decision support; and AI-based student progress evaluation, and personalized education. Its implementation will inarguably change the current concept of teaching Endodontics. Dental educators would benefit from introducing AI in clinical and didactic pedagogy; however, they must be aware of AI's limitations and challenges to overcome.

Validity and reliability of artificial intelligence chatbots as public sources of information on endodontics

AIM

This study aimed to evaluate and compare the validity and reliability of responses provided by GPT-3.5, Google Bard, and Bing to frequently asked questions (FAQs) in the field of endodontics.

METHODOLOGY

FAQs were formulated by expert endodontists (n = 10) and collected through GPT-3.5 queries (n = 10), with every question posed to each chatbot three times. Responses (N = 180) were independently evaluated by two board-certified endodontists using a modified Global Quality Score (GQS) on a 5-point Likert scale (5: strongly agree; 4: agree; 3: neutral; 2: disagree; 1: strongly disagree). Disagreements on scoring were resolved through evidence-based discussions. The validity of responses was analysed by categorizing scores into valid or invalid at two thresholds: The low threshold was set at score ≥4 for all three responses whilst the high threshold was set at score 5 for all three responses. Fisher's exact test was conducted to compare the validity of responses between chatbots. Cronbach's alpha was calculated to assess the reliability by assessing the consistency of repeated responses for each chatbot.

RESULTS

All three chatbots provided answers to all questions. Using the low-threshold validity test (GPT-3.5: 95%; Google Bard: 85%; Bing: 75%), there was no significant difference between the platforms (p > .05). When using the high-threshold validity test, the chatbot scores were substantially lower (GPT-3.5: 60%; Google Bard: 15%; Bing: 15%). The validity of GPT-3.5 responses was significantly higher than Google Bard and Bing (p = .008). All three chatbots achieved an acceptable level of reliability (Cronbach's alpha >0.7).

CONCLUSIONS

GPT-3.5 provided more credible information on topics related to endodontics compared to Google Bard and Bing.

Artificial Intelligence for Detection of External Cervical Resorption Using Label-Efficient Self-Supervised Learning Method

INTRODUCTION

The aim of this study was to leverage label-efficient self-supervised learning (SSL) to train a model that can detect ECR and differentiate it from caries.

METHODS

Periapical (PA) radiographs of teeth with ECR defects were collected. Two board-certified endodontists reviewed PA radiographs and cone beam computed tomographic (CBCT) images independently to determine presence of ECR (ground truth). Radiographic data were divided into 3 regions of interest (ROIs): healthy teeth, teeth with ECR, and teeth with caries. Nine contrastive SSL models (SimCLR v2, MoCo v2, BYOL, DINO, NNCLR, SwAV, MSN, Barlow Twins, and SimSiam) were implemented in the assessment alongside 7 baseline deep learning models (ResNet-18, ResNet-50, VGG16, DenseNet, MobileNetV2, ResNeXt-50, and InceptionV3). A 10-fold cross-validation strategy and a hold-out test set were employed for model evaluation. Model performance was assessed via various metrics including classification accuracy, precision, recall, and F1-score.

RESULTS

Included were 190 PA radiographs, composed of 470 ROIs. Results from 10-fold cross-validation demonstrated that most SSL models outperformed the transfer learning baseline models, with DINO achieving the highest mean accuracy (85.64 ± 4.56), significantly outperforming 13 other models (P < .05). DINO reached the highest test set (ie, 3 ROIs) accuracy (84.09%) while MoCo v2 exhibited the highest recall and F1-score (77.37% and 82.93%, respectively).

CONCLUSIONS

This study showed that AI can assist clinicians in detecting ECR and differentiating it from caries. Additionally, it introduced the application of SSL in detecting ECR, emphasizing that SSL-based models can outperform transfer learning baselines and reduce reliance on large, labeled datasets.

Outcomes and predictive factors of vital pulp therapy in a large-scale retrospective cohort study over 10 years

This cohort study evaluated the long-term success/survival of vital pulp therapies (VPTs) after carious pulp exposure in adult teeth. Additionally, factors influencing long-term success were identified. Teeth treated during 2011-2022 in a private clinic were studied with clinical/radiographic follow-ups. Data included patient demographics, tooth specifics, and treatment details. Outcomes were classified as success/failure based on clinical/radiographic findings, with tooth functionality determining the survival rate. Encompassing 1149 patients and 1257 VPT-treated teeth, the average monitoring period was 42.2 months. Overall VPTs' survival and success rates were 99.1% and 91.6%, respectively. Success rates for 768 direct pulp cappings, 217 miniature pulpotomies, and 272 full pulpotomies were 91.9%, 92.6%, and 90.1%, respectively (P > 0.05). Influencing factors included symptomatic irreversible pulpitis (SIP; HR 1.974, 95% CI 1.242-3.137; P = 0.004), radiographic signs of apical periodontitis (AP; HR 2.983, 95% CI 1.961-4.540; P < 0.001), restoration type (HR 2.263, 95%CI 1.423-3.600; P = 0.001), and restoration surfaces (HR 1.401, 95%CI 1.034-1.899; P = 0.030). This study concludes that VPT techniques consistently exhibit high long-term success/survival rates in treating carious pulp exposures. Critical predictors include initial clinical signs of SIP/AP, caries extent, and use of composite restorations.

Flare-ups After Nonsurgical Retreatments: Incidence, Associated Factors, and Prediction

INTRODUCTION

The aims of this study were to determine the incidence, associated factors, and predictability of flare-ups after nonsurgical retreatments (NSRetx).

METHODS

All patients (n = 3,666) who received NSRetx by 3 endodontists in 2 endodontic offices during a period of 6 years (2016-2022) were included. Demographic, diagnostic, and procedural data were collected. A flare-up was defined as moderate-severe pain with/without swelling that took place within 14 days of initiation of NSRetx and resulted in an unscheduled appointment. Bivariate analyses on the entire cohort and multivariable analyses on cases with complete dataset (n = 2,846) were performed to identify significant associations. A Random Forest algorithm was used to make a prediction model.

RESULTS

Incidence of flare-ups was 3.95% (n = 145). Increased risk of flare-ups was associated with diabetes (adjusted odds ratio [AOR] = 2.01; 95% confidence interval [CI], 1.01-3.97), mandibular teeth (AOR = 1.67; 95% CI, 1.11-2.52), moderate-severe preoperative pain on percussion (AOR = 2.13; 95% CI, 1.31-3.50), and pain on palpation (AOR = 1.63; 95% CI, 1.01-2.64). Lower risk of flare-up was associated with high blood pressure (AOR = 0.44; 95% CI, 0.21-0.82) (P < .05). The prediction model was not able to predict flare-ups with sufficient confidence (precision = 0.13).

CONCLUSIONS

Incidence of flare-ups following NSRetx was low (∼4%) and had a weak but significant association with the history of diabetes. Moderate-severe pain on percussion, pain on palpation (any intensity), and mandibular teeth had a significant association with flare-ups. The history of high blood pressure was associated with lower risk of flare-ups. Flare-ups were difficult to predict in this clinical setting.

Was the Coronavirus Disease 2019 Pandemic Associated with an Increased Rate of Cracked Teeth?

INTRODUCTION

There is lack of data on whether the coronavirus disease 2019 (COVID-19) pandemic was associated with changes in the etiology of pathosis in endodontic patients. The aim of this study was to determine the rate of cracks and other etiologic factors during the period of March 16th to May 31st in 2020 (COVID-19 initial outbreak) and 2021 (COVID-19 ongoing pandemic) compared with figures from the same period in 2019 (pre-COVID era) in 2 endodontists' practices.

METHODS

The etiologies of patients' chief complaints were determined from records of 2440 teeth (740 in 2019, 651 in 2020, and 1049 in 2021). Changes in the proportion of etiologic factors among all 3 periods were analyzed. The association between the rate of cracked teeth and patients' age and sex was determined using a logistic regression model.

RESULTS

The rates of all etiologies collectively during the studied periods showed a significant change (P < .0001). The rate of cracks significantly increased in 2020 (11.8%) (P = .0001) and 2021 (8%) (P = .0018) compared with 2019 (4.3%). The rate of persistent infections decreased in 2020 (22.3%) (P = .0013) and then increased in 2021 (27.5%) (P = .0153) compared with 2019 (30%). Cracked teeth were associated with the age group of 40-60 years (odds ratio [OR] = 1.882; 95% confidence interval [CI], 1.063-3.330) in 2020 and with age ranges of 40-60 years (OR = 2.051; 95% CI, 1.120-3.759) and >60 years (OR = 2.038; 95% CI, 1.050-3.956) and male sex (OR = 1.599; 95% CI, 1.019-2.510) in 2021.

CONCLUSIONS

The rate of cracked teeth increased during the initial outbreak of the COVID-19 pandemic and 1 year later. This study provided evidence on the association between the COVID-19 pandemic and changes in the rate and presentation of endodontic etiologic factors.

Regenerative Endodontic Treatment Using Periapical Blood or Circulating Blood as Scaffold: A Volumetric Analysis

INTRODUCTION

Circulating blood is a readily available scaffold when enough bleeding cannot be induced from periapical tissues during regenerative endodontic treatments (RET). The aim of this investigation was to compare the radiographic outcome, linear and 3-dimensional volumetric, of RET using periapical blood or circulating blood as scaffolds in sheep immature mandibular incisors.

METHODS

Thirty-two immature sheep mandibular central incisors were randomly assigned to the following groups (n=8)- Positive control: the pulps were removed without any treatment; Periapical blood: RET was performed using periapical blood as scaffold; Circulating blood: RET was performed using circulating blood as scaffold; Negative control: intact teeth without any treatment. After 8 months micro computed tomography images of mandibular blocks were taken to assess the followings: root length; root thickness at mid-root and CEJ levels; and incidence of apical closure. Root structures were segmented, and root volumes were calculated and analyzed statistically.

RESULTS

RET using periapical blood and circulating blood resulted in increase in root length, root wall thickness at mid-root and CEJ levels, incidence of apical closure, and root volume (P<.05). There were no significant differences between RET groups and negative control group regarding linear measurements (i.e., root length, root thickness, and apical closure) (P>.05). Root volumes of the two RET groups were similar (P>.05) and were less than those observed in negative control group (P<.05).

CONCLUSIONS

There were no significant radiographic differences between RET groups using periapical blood and circulating blood as scaffolds. RET resulted in less root volume compared to normal root development.

Endodontics Specialists' Practice during the Initial Outbreak of Coronavirus Disease 2019

INTRODUCTION

The first outbreak of coronavirus disease 2019 (COVID-19) in the United States resulted in a nationwide closure of dental offices that created an oral health crisis. The aim of this observational study was to analyze and compare the characteristics of patients who visited 2 private endodontics offices from March 16 to May 31, 2020, compared with the same period in 2019.

METHODS

Demographic, diagnostic, and procedural data of 1520 (693 in 2020 and 827 in 2019) patient visits were collected. Bivariate and multiple logistic regression analyses were used to assess the impact of the COVID-19 outbreak on patient-related variables.

RESULTS

Bivariate analyses showed that the number of patient visits decreased in April and May 2020 (P < .0001). In 2020, patients' self-reported pain level was higher, they were more frequently diagnosed with pulp necrosis and acute apical abscess, and they received more incisions for drainage (P < .05). Multiple logistic regression analyses showed that the COVID-19 outbreak was associated with less visits for older patients (>49.5 years) (odds ratio [OR] = 0.720; 95% confidence interval [CI], 0.573-0.906), more patients with kidney diseases (OR = 2.690; 95% CI, 1.143-6.331), higher levels of pain on percussion (OR = 2.277; 95% CI, 1.718-3.016), less cases with previously initiated treatment (OR = 0.242; 95% CI, 0.080-0.731), less periapical diagnoses of asymptomatic apical periodontitis (OR = 0.510; 95% CI, 0.306-0.849), and a higher number of nonsurgical root canal treatments (OR = 2.073; 95% CI, 1.397-3.074) and apicoectomies (OR = 2.799; 95% CI, 1.367-5.729).

CONCLUSIONS

These findings show that the public health burden of endodontic infections was more intense during the initial outbreak of COVID-19.

Revitalizing previously treated teeth with open apices: A case report and a literature review

Revitalizing the root canals of previously treated teeth with open apices is appealing to clinicians and patients. However, there are fundamental differences in the microbiome and the microenvironment between a canal with a primary endodontic infection and a canal with a persistent endodontic infection. The aims of this report are to report a case where a previously treated tooth with an open apex and a large apical radiolucency was treated successfully using regenerative endodontic treatment (RET) and to review and critically appraise the literature on procedures and outcomes of RET that result in revitalization of canal(s) in previously treated teeth with open apices. A maxillary central incisor with poor-quality root filling, a large apical radiolucency and an open apex was retreated using RET using platelet-rich fibrin as the scaffold. After 24 months, there was complete healing of the periapical lesion and obvious radiographic signs of apical root closure. Electronic searches were performed in MEDLINE, Scopus and Embase, and the baseline, procedural and outcome data of qualified articles were collected. An assessment tool was developed to rate the quality of evidence reported in these case report/series. Nine articles, three case series and six case reports, with a total of 17 teeth of all types, were included in the reports identified. The age of patients ranged from 7 to 48 years (mean: 19.4 years). The recall period ranged from 12 to 72 months (mean: 29 months). All 17 teeth survived and were functional with healing/healed outcomes. "Apical closure" was the most common radiographic finding regarding root development. The quality of evidence using the new assessment tool was rated "Excellent" in three case reports but only "Fair" in the other six articles. The present case report, as well as the review of the literature, suggests that revitalizing the root canal system of teeth with open apices and post-treatment disease using RET is a potentially valid treatment option. However, more clinical studies with higher levels of evidence and higher quality of evidence are required to confirm the viability of this treatment approach.

Accuracy and efficiency of guided root-end resection using a dynamic navigation system: a human cadaver study

AIM

To determine and compare the accuracy and efficiency of a dynamic navigation system (DNS) with a freehand (FH) technique when conducting root-end resection in a human cadaver model.

METHODOLOGY

Forty roots in cadaver heads were included and divided into two groups: DNS (n = 20) and FH (n = 20). Cone beam computed tomography (CBCT) scans of all teeth were taken. The drilling path and depth were planned virtually to using the X-guide software (X-Nav Technologies, Lansdale, PA, USA). Osteotomy and root-end resection were done under navigation in the DNS group, and freehand under the dental operating microscope in the FH group. Post-operative CBCTs were taken. Linear deviations, angular deflection, time of operation and number of mishaps were compared with determine the accuracy and efficiency. Shapiro-Wilk, one-way ANOVA and Fisher exact tests were used (P < 0.05).

RESULTS

Linear deviations, angular deflection and operation time were significantly less in the DNS group (P < 0.05). The number of mishaps was not different between the two groups (P > 0.05). Subgroup analyses revealed that the distance of >5 mm from buccal cortical plate was significantly associated with lower accuracy, increased operation time and greater incidence of mishaps in the FH group (P < 0.05), but not in the DNS group.

CONCLUSIONS

The dynamic navigation system was more accurate and more efficient in root-end resection in a cadaver model than the freehand technique. The distance of the roots from the buccal cortical plate had a significant negative impact on the accuracy and efficacy of the root-end resection procedure when using the freehand technique. The dynamic navigation system has the potential to be a safe and reliable technological addition to endodontic microsurgery.

Non-Hodgkin Lymphoma Mimicking Endodontic Lesion: A Case Report with 3-dimensional Analysis, Segmentation, and Printing

Non-Hodgkin lymphoma (NHL) of the oral cavity can present with pain, swelling and radiolucent lesion mimicking endodontic diseases. This article reports on a case of diffuse large B-cell lymphoma initially diagnosed and treated as periodontal disease and then endodontic disease in the maxillary anterior and premolar area of a 40-year old female. A cone beam computed tomography (CBCT) image of the lesion was taken. The lesion was segmented using Mimics software (Materialise NV, Lueven, Belgium). Three-dimensional models of the tumor were printed. During the surgical phase teeth #4, 6, and 7 were extracted and biopsy samples were obtained. Histopathologic examination showed invasive sheets of large, atypical, basophilic cells strongly and diffusely positive for CD20. Three-dimensional analysis, segmentation, and printing of radiolucent lesions of the jaws assists with differential diagnosis and efficient treatment. Oral health professionals can play a crucial role in the early detection and diagnosis of oral NHL, thereby preventing extensive loss of function and esthetics, and even saving lives.

Postoperative Pain: An Analysis on Evolution of Research in Half-Century

INTRODUCTION

Examining the evolution of research parameters helps scientists to discover the well-developed and neglected aspects of knowledge. Pain after root canal treatment is a health problem affecting millions of patients. Research in this field has a meaningful impact on quality of lives. The aim of this study was to analyze the evolution of research on postoperative pain over the past 50 years.

METHODS

Electronic searches were performed in Scopus and MEDLINE databases to identify studies on pain after nonsurgical root canal treatments/retreatments. The full texts of eligible articles were reviewed to determine the study category and to extract and analyze the methodological variables. A series of statistical analyses were performed to determine the trend of publications based on the variable of interest over time.

RESULTS

Four hundred twenty-four articles were included. There was a positive trend for systematic reviews, studies with sample size <200, studies on single-visit treatment, and clinical trials on instrumentation and adjunct treatments (P < .05). There was a negative trend for the use of numeric rating scales, studies on multiple-visit treatments, clinical trials on medication/medicament, and studies on pain in maxillary incisors (P < .05). No trend was observed based on pulpal diagnosis or for studies with longer observation periods (>8 weeks) (P > .05).

CONCLUSIONS

A paradigm shift is needed toward clinical studies with larger sample sizes, longer observation periods, and more focus on pulpal diagnoses associated with higher rates of postoperative pain. There is a need to view postoperative pain as an important patient-centered outcome and to develop and disseminate standard reporting guidelines for future studies.

Clinical, Radiographic, and Histologic Outcome of Regenerative Endodontic Treatment in Human Teeth Using a Novel Collagen-hydroxyapatite Scaffold

INTRODUCTION

Histologic examination of teeth after regenerative endodontic treatment (RET) shows that the type, quality, and quantity of tissues formed in the root canal space are not predictable. The aim of this study was to examine clinically, radiographically, and histologically the outcome of RET in immature noninfected human teeth using SynOss Putty (Collagen Matrix Inc, Oakland, NJ) as a scaffold.

METHODS

Three pairs of maxillary/mandibular first premolars in 3 patients scheduled for extraction were included. Sensibility tests confirmed the presence of vital pulps. After informed consent, anesthesia, and rubber dam isolation, the pulps were removed. RET was performed using the following scaffolds: SynOss Putty + blood in both teeth in patient #1, SynOss Putty with or without blood in patient #2, and SynOss Putty + blood or blood only in patient #3. After a follow-up period of 2.5-7.5 months, the teeth were clinically and radiographically evaluated, extracted, and examined histologically.

RESULTS

Patients remained asymptomatic after treatment. Radiographic examination of the teeth showed signs of root development after treatment. In teeth treated with SynOss Putty + blood, histologic examination showed formation of intracanal mineralized tissue around the scaffold particles solidifying with newly formed cementumlike tissue on the dentinal walls. The tooth treated with SynOss Putty without blood showed the formation of a periapical lesion. The tooth treated with a blood clot only showed tissues of periodontal origin growing into the root canal space.

CONCLUSIONS

SynOss Putty + blood showed a predictable pattern of tissue formation and mineralization when used as a scaffold for RET in human immature noninfected teeth. The newly formed mineralized tissue solidifies with newly formed cementum on the dentinal walls.

Periodontal healing following non-surgical repair of an old perforation with pocket formation and oral communication

Iatrogenic perforations negatively impact the outcome of endodontic treatments. Studies on prognostic factors showed that perforations in the coronal third of the root with periodontal pocket formation have an unfavorable prognosis. A 36-year-old female was referred for endodontic evaluation of tooth #13 with a history of an iatrogenic perforation, happened 3 years ago. There was a sinus tract associated with perforation, 10 mm probing on the mesial and mesio-palatal, bleeding on probing, radiolucent lesion adjacent to the perforation and complete resorption of the interdental bone between teeth #13 and #12. After the treatment options were discussed, she chose to save the tooth. The tooth was accessed under rubber dam isolation, the perforation site was cleaned and disinfected using 0.5% sodium hypochlorite and sealed with calcium-enriched mixture cement. Eighteen months after treatment the tooth was functional and asymptomatic. The probing depths were normal without bleeding on probing. Radiographically, the interdental crestal bone formed between teeth #13 and #12. Despite all negative prognostic factors in this case (i.e., perforations in the coronal third, pocket formation, and radiolucent lesion), healing was unexpectedly achieved via non-surgical repair of the perforation. Further research on biological aspects of healing in the periodontium following iatrogenic perforations are recommended.

Hazards of Improper Dispensary: Literature Review and Report of an Accidental Chloroform Injection

Several clear, transparent solutions are used in endodontics. Inappropriate dispensing methods can lead to accidental injection or accidental irrigation. These accidents can cause permanent tissue damage including damage to the bone, periodontium, nerves, and vasculature. This article reports on the consequences of an accidental chloroform injection. Nonsurgical retreatment of tooth #8 was planned as part of a restorative treatment plan in a 69-year-old woman. The dentist accidentally injected chloroform instead of local anesthesia because chloroform was loaded into the anesthetic syringe. The patient experienced severe pain and swelling and soft tissue necrosis and suffered permanent sensory and motor nerve damage. A review of the literature was performed on accidents caused by improper dispensary, namely accidental injections and accidental irrigations. The data were extracted and summarized. Sodium hypochlorite, chlorhexidine, formalin, formocresol, 1:1000 adrenaline, benzalkonium chloride, and lighter fuel were accidentally injected as an intraoral nerve block or as infiltration injections. Bone and soft tissue necrosis, tooth loss, and sensory nerve damage (anesthesia and paresthesia) were the most common consequences reported. Such disastrous events can be prevented by appropriate labeling and separate dispensing methods for each solution. There is a need for disseminating information on toxicity and biocompatibility of materials/solutions used in endodontics. The authors recommend training dental students and endodontic residents on immediate and long-term therapeutic management of patients when an accidental injection or accidental irrigation occurs.

Non-Surgical Retreatment of Maxillary Lateral Incisor with Unusual Anatomy: A Case Report and Mini Review

Knowledge about internal anatomy plays a crucial role in the success of the root canal treatment. Many studies on internal anatomy have repeatedly reported that maxillary lateral incisors have only one canal. The primary aim of this article was to describe successful non-surgical retreatment of a permanent maxillary lateral incisor with two root canals and open apices. The treatment was carried out using dental operating microscope and the canals were obturated with mineral trioxide aggregate (MTA) as an apical plug. A review of literature was also conducted to evaluate the anatomical variations of maxillary lateral incisors.

Isolation, Characterization, and Differentiation of Dental Pulp Stem Cells in Ferrets

INTRODUCTION

The ferret canine tooth has been introduced as a suitable model for studying dental pulp regeneration. The aim of this study was to isolate and characterize ferret dental pulp stem cells (fDPSCs) and their differentiation potential.

METHODS

Dental pulp stem cells were isolated from freshly extracted ferret canine teeth. The cells were examined for the expression of stem cell markers STRO-1, CD90, CD105, and CD146. The osteo/odontogenic and adipogenic differentiation potential of fDPSCs was evaluated. Osteogenic and odontogenic marker genes were evaluated using quantitative real-time polymerase chain reaction (qRT-PCR) on days 1, 4, and 8 after osteo/odontogenic induction of fDPSCs including dentin sialophosphoprotein (DSPP), dentin matrix protein-1, osteopontin, and alkaline phosphatase. Human dental pulp cells were used as the control. The results were analyzed using 3-way analysis of variance.

RESULTS

fDPSCs were positive for STRO1, CD90, and CD105 and negative for CD146 markers with immunohistochemistry. fDPSCs showed strong osteogenic and weak adipogenic potential. The overall expression of DSPP was not significantly different between fDPSCs and human dental pulp cells. The expression of DSPP in osteo/odontogenic media was significantly higher in fDPSCs on day 4 (P < .01). The overall expression of dentin matrix protein-1, osteopontin, and alkaline phosphatase was significantly higher in fDPSCs (P = .0005).

CONCLUSIONS

fDPSCs were positive for several markers of dental pulp stem cells resembling human DPSCs and appeared to show a stronger potential to differentiate to osteoblastic rather than odontoblastic lineage.

Efficacy of Er,Cr:YSGG laser in removing smear layer and debris with two different output powers

OBJECTIVE

The purpose of this study was to evaluate the effectiveness of the erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser in removing debris and the smear layer using two different output powers on the apical, middle, and coronal segments of root canal walls.

BACKGROUND DATA

Previous literature has failed to evaluate the exclusive effect of Er,Cr:YSGG laser on the quality of smear layer and debris removal in all three segments of the root canal space.

METHODS

Sixty extracted teeth were included in the study. After instrumentation, samples were divided into three experimental groups and one positive control group with no further treatment. In group 1, a final irrigation was performed using ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl), sequentially. In group 2, the samples were treated with a 2.78 μm Er,Cr:YSGG laser with an output power of 1.5 W. The same laser was used in group 3, but with an output power of 2.5 W. Scanning electron microscope (SEM) images from the coronal, middle, and apical thirds of the roots were prepared and evaluated for both smear layer and debris removal by three blinded observers.

RESULTS

The results showed no differences between groups 1 and 2 regarding the quality of smear layer removal in all areas. However, the 2.5 W laser failed to remove the smear layer effectively. Regarding debris removal, the EDTA and NaOCl irrigation showed significantly better outcomes (adjusted p<0.05) in all areas.

CONCLUSIONS

This study raises questions about the overall cleaning abilities of Er,Cr:YSGG lasers.

Concurrent intentional replantation of maxillary molars using a novel root-end filling

This article describes the successful concurrent intentional replantation (IR) of 2 maxillary molars. A 28-year-old woman complained of repeated swelling and pain in the left maxilla when chewing. Teeth No. 14 and 15 were sensitive to percussion and palpation. Radiographs revealed a large periapical radiolucent lesion and inadequate root canal fillings in both teeth. The patient refused nonsurgical retreatment, periradicular surgery, or implant replacement as treatment options, so IR was chosen. After the extraction of tooth No. 14, root-end resection and root-end preparation of the 3 roots were completed. All root-end cavities were filled with calcium enriched mixture cement and the tooth was replanted. The same procedure was done for tooth No. 15. The patient was recalled 1, 7, and 14 days post-treatment for clinical evaluations. Follow-up visits at 6, 10, 15, and 24 months postsurgery revealed that both teeth were functional with no signs or symptoms of inflammation or resorption. The periapical lesion was healed at 24 months.

Surgical management of a failed internal root resorption treatment: a histological and clinical report

This article presents the successful surgical management of a failed mineral trioxide aggregate (MTA) orthograde obturation of a tooth with a history of impact trauma and perforated internal root resorption. A symptomatic maxillary lateral incisor with a history of perforation due to internal root resorption and nonsurgical repair using MTA was referred. Unintentional overfill of the defect with MTA had occurred 4 yr before the initial visit. The excess MTA had since disappeared, and a radiolucent lesion adjacent to the perforation site was evident radiographically. Surgical endodontic retreatment was performed using calcium enriched mixture (CEM) cement as a repair material. Histological examination of the lesion revealed granulation tissue with chronic inflammation, and small fragments of MTA encapsulated within fibroconnective tissue. At the one and two year follow up exams, all signs and symptoms of disease had resolved and the tooth was functional. Complete radiographic healing of the lesion was observed two years after the initial visit. This case report illustrates how the selection of an appropriate approach to treatment of a perforation can affect the long term prognosis of a tooth. In addition, extrusion of MTA into a periradicular lesion should be avoided.

Tissue engineering considerations in dental pulp regeneration

Regenerative endodontic procedure is introduced as a biologically based treatment for immature teeth with pulp necrosis. Successful clinical and radiographic outcomes following regenerative procedures have been reported in landmark case reports. Retrospective studies have shown that this conservative treatment allows for continued root development and increases success and survival rate of the treated teeth compared to other treatment options. Although the goal of treatment is regeneration of a functional pulp tissue, histological analyses show a different outcome. Developing predictable protocols would require the use of key elements for tissue engineering: stem cells, bioactive scaffolds, and growth factors. In this study we will review the evidence based steps and outcomes of regenerative endodontics.

A preliminary report on histological outcome of pulpotomy with endodontic biomaterials vs calcium hydroxide

Objectives

The purpose of the study was to evaluate human dental pulp response to pulpotomy with calcium hydroxide (CH), mineral trioxide aggregate (MTA), and calcium enriched mixture (CEM) cement.

Materials and Methods

A total of nine erupted third molars were randomly assigned to each pulpotomy group. The same clinician performed full pulpotomies and coronal restorations. The patients were followed clinically for six months; the teeth were then extracted and prepared for histological assessments. The samples were blindly assessed by an independent observer for pulp vitality, pulp inflammation, and calcified bridge formation.

Results

All patients were free of clinical signs/symptoms of pulpal/periradicular diseases during the follow up period. In CH group, one tooth had necrotic radicular pulp; other two teeth in this group had vital uninflamed pulps with complete dentinal bridge formation. In CEM cement and MTA groups all teeth had vital uninflamed radicular pulps. A complete dentinal bridge was formed beneath CEM cement and MTA in all roots. Odontoblast-like cells were present beneath CEM cement and MTA in all samples.

Conclusions

This study revealed that CEM cement and MTA were reliable endodontic biomaterials in full pulpotomy treatment. In contrast, the human dental pulp response to CH might be unpredictable.

The effect of Er,Cr:YSGG laser irradiation on the push-out bond strength of RealSeal self-etch sealer

OBJECTIVE

The aim of this study was to evaluate the effect of an erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser on the push-out bond strength of RealSeal Self-Etch (SE) sealer.

BACKGROUND DATA

Various methods are used for smear layer removal in endodontics, such as the application of Er,Cr:YSGG lasers. This laser system may influence the bond strength of resin-based sealers.

METHODS

Sixty single-rooted extracted teeth were selected. After root canal preparation, samples were divided into two experimental groups and one positive control group (n=20 per group). In group 1, the smear layer was removed by irrigation with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl). In group 2, the smear layer was removed using a 2.78 μm Er,Cr:YSGG laser with radial firing tips (RFT3) (parameters: 1.5 W, 140 μs, 20 Hz, and 15% water to 15% air ratio), moving at 2 mm/sec in an apico-coronal direction. Group 3 served as a positive control group. Five specimens from each group were selected for scanning electron microscope (SEM) observation. The remaining 45 roots were obturated with RealSeal SE/Resilon and subjected to push-out tests. Data were analyzed using one way analysis of variance (ANOVA) and Tamhane's test.

RESULTS

The results showed no significant difference between push-out bond strength of root canal fillings in the EDTA+NaOCl group and the 1.5 W laser group (p>0.05). The positive control group showed the lowest push-out bond strength.

CONCLUSIONS

The results of the present study indicate that the application of an Er,Cr:YSGG laser with radial firing tips did not adversely affect the push-out bond strength of RealSeal SE sealer to dentin.

Evaluation of the effect of blood contamination on the compressive strength of MTA modified with hydration accelerators

Objectives

This study was performed to evaluate the effect of blood contamination on the compressive strength (CS) of Root MTA (RMTA) modified with Calcium chloride (CaCl₂) and Disodium hydrogen phosphate (Na₂HPO₄) as setting accelerators over time.

Materials and Methods

A total of 110 cylindrical specimens of RMTA were divided into 6 experimental groups as follows: Group1, RMTA; Group 2, RMTA modified with CaCl₂ (RMTA-C); Group 3, RMTA modified with Na₂HPO₄ (RMTA-N); Group 4, RMTA contaminated with blood; Group 5, RMTA-C contaminated with blood; Group 6, RMTA-N contaminated with blood. The CS of specimens in all groups was evaluated after 3 hr, 24 hr, and 1 wk. In the modified groups (groups 2, 3, 5, and 6) the CS of five specimens per group was also evaluated after 1 hr.

Results

Blood contamination significantly reduced the CS of all materials at all time intervals (p < 0.05). After 3 hr, the CS of specimens in the RMTA groups (with and without blood contamination) was significantly lower than those in the RMTA-C and RMTA-N groups (p < 0.05). The CS values were not significantly different at the other time intervals. In all groups, the CS of specimens significantly increased over time (p < 0.05).

Conclusions

Blood contamination decreased the CS of both original and accelerated RMTA.

Stability of Doxycycline Absorbed on Root Canal Dentin After Obturation with Gutta-Percha/AH26 and Resilon/RealSeal at Different Time Intervals

OBJECTIVE

Eradication of microorganisms present in the root canal system is paramount for the successful outcome of root canal therapy. The purpose of this study was to compare the of doxycycline absorbed from MTAD into root canal dentin after obturation with gutta-percha/AH26 and Resilon/RealSeal at different time intervals.

MATERIALS AND METHODS

Fifty-one extracted human teeth were instrumented. Thirty samples were obturated with either gutta-percha/AH26 or Resilon/self-etch RealSeal after final irrigation with MTAD. Fifteen samples were kept unobturated (positive control); six samples were obturated with either gutta-percha/AH26 or Resilon/self-etch RealSeal without MTAD irrigation (negative control). After aging for 1, 3 or 6 weeks, dentin debri were collected, the Doxycycline compound was extracted and its amount was quantified using high performance liquid chromatography. The statistical significance of the change in Doxycycline concentrations was tested with two-way ANOVA.

RESULTS

The mean concentration of Doxycycline in dentin for one, three and six-week guttapercha/AH26 samples was 1.8±0.36, 1.22±0.22 and 0.67±0.11 respectively, whereas these concentrations in Resilon/RealSeal samples were 1.60±0.26, 0.80±0.14 and 0.59±0.01 respectively. Regarding the positive control group, these concentrations were 2.09±0.11, 1.54±0.12 and 0.72±0.07 respectively for 1, 3 and 6-week intervals. No Doxycycline was detected in negative control groups. The Doxycycline concentrations showed a significant difference forobturating materials (p=0.008). These concentrations were higher in the gutta-percha/AH26 samples than Resilon/RealSeal samples in each time interval.

CONCLUSION

The remaining amount of Doxycycline bonded to dentin was higher when root canals were obturated with gutta-percha/AH26 compared to Resilon/RealSeal. The stability of Doxycycline showed a time dependent decrease.

Pulpotomy in caries-exposed immature permanent molars using calcium-enriched mixture cement or mineral trioxide aggregate: a randomized clinical trial

OBJECTIVE

To compare clinical and radiographic outcomes of pulpotomy treatment using calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA) in carious-exposed vital immature permanent first molars.

DESIGN

Fifty-one immature molars with clinical carious exposure with symptomatic/asymptomatic pulpitis met the inclusion criteria and randomly assigned to one of the treatment groups (CEM [26 teeth; 59 roots], MTA [25 teeth; 59 roots]). After performing pulpotomy and covering the radicular pulps with the biomaterials, all teeth were permanently restored. Blinded clinical and radiographic evaluations were performed at 6 and 12 months after operation for signs of success or failure. Radiographs were evaluated for complete/partial apical closure. The data were analysed using chi-square test and generalized estimating equation (GEE) model.

RESULTS

There was no significant difference at the baseline between the two experimental groups. All available cases (49 teeth) showed pulp survival and signs of continuous root development after 12 months. Overall, complete apical closure (apexogenesis) occurred in 76.8% and 73.8% of radiographically interpreted roots in CEM cement and MTA groups, respectively. There was no statistical difference in terms of radiographic outcomes between two groups.

CONCLUSIONS

Calcium-enriched mixture cement and MTA showed similar performance in pulpotomy of immature caries-exposed permanent molars.

Extensive idiopathic external root resorption in first maxillary molar: a case report

External root resorption of permanent teeth is a multifactorial process. Several etiologic and predisposing factors have been related to external root resorption. Idiopathic external root resorption is defined as cases of external root resorption without a distinct etiologic factor. This article presents an extensive idiopathic external root resorption of maxillary first molar with irreversible pulpitis in an 18-year-old patient. The resorption was diagnosed in conventional radiographs and confirmed with Cone Beam Computed Tomography (CBCT) images. Unlike other reports in this field, and despite the severe resorption of all roots, there was no abnormal tooth mobility. Cold and electric pulp tests confirmed tooth vitality and revealed irreversible pulpitis. Therefore the exact etiology of the resorption remained unclear. Considering the poor prognosis due to severe root resorption, extraction and implant replacement was indicated.

Calcium-enriched mixture cement as artificial apical barrier: A case series

In comparison to the conventional apexification using calcium hydroxide, artificial apical barrier technique is more valuable and less time consuming. This article describes successful use of calcium-enriched mixture (CEM) cement as an artificial apical barrier in open apices. In this study, 13 single-rooted teeth with necrotic pulps and open apices were treated non-surgically. After copious irrigation of the root canals with NaOCl 5.25% and gentle filing, based on need for interappointment dressing, treatments were followed by CEM cement (BioniqueDent, Tehran, Iran) apical plug insertion in the first or second appointment. All cases were then permanently restored. All subjects were followed until radiographic evidence of periradicular healing was seen (mean 14.5 months). Clinically, all cases were functional and asymptomatic and complete osseous healing was observed in all the teeth. Considering the biological properties of CEM cement, this new endodontic biomaterial might be appropriate to be used as artificial apical barrier in the open apex teeth.

Periapical Healing After Direct Pulp Capping With Calcium-enriched Mixture Cement: A Case Report

This article describes a successful direct pulp capping of a mature symptomatic mandibular second molar in a 14-year-old girl. The patient was referred with sensitivity to cold beverages and pain on chewing on the second left mandibular molar. Clinical examinations revealed extensive coronal caries and sensitivity to percussion. Radiographically, the tooth was mature and had a widened apical periodontal ligament (PDL) and a narrow periapical lesion. The concluding diagnosis was symptomatic irreversible pulpitis with symptomatic apical periodontitis. Treatment included caries removal under rubber dam isolation, capping of exposure sites with calcium-enriched mixture (CEM) cement, and permanent coronal restoration. At three-, 10-, and 15-month follow-up, the tooth was functional, had normal response to cold test, and did not have sensitivity to percussion. The PDL space regained its normal width, and the periapical lesion healed.

Drawbacks and unfavorable outcomes of regenerative endodontic treatments of necrotic immature teeth: a literature review and report of a case

INTRODUCTION

Endodontic treatment of immature necrotic teeth is challenging. Recently a biologically based treatment called regenerative endodontic treatment was introduced. Although regenerative endodontic treatment causes root development, there are several drawbacks and unfavorable outcomes that should be addressed. This article describes regenerative endodontic treatment of 2 maxillary central incisors with poor root development outcomes.

METHODS

A healthy 14-year-old female patient was referred. The patient had history of an impact trauma 6 years before the first visit. Clinical and radiographic examinations revealed that maxillary central incisors were immature and necrotic with symptomatic apical periodontitis. After local anesthesia, rubber dam isolation, and access cavity preparation each tooth was irrigated with 20 mL of NaOCl 5.25% and received triple antibiotic dressing (ciprofloxacin, metronidazole, minocycline) for 4 weeks. In the next visit, after eliminating antibiotic dressing, bleeding was induced inside the canals, and then the coronal thirds of the canals were sealed with mineral trioxide aggregate. A week later, both teeth were permanently restored.

RESULTS

In clinical and radiographic follow-ups, both teeth were functional, periapical lesions were healed, and the apices formed. However, the roots were not developed. After 6 years, because of moderate discoloration and caries, both teeth received root canal therapy and were permanently restored with casting dowel core and full crown restorations.

CONCLUSIONS

Criteria for case selection in regenerative endodontic treatments should be determined.

Regenerative endodontic treatment (revascularization) for necrotic immature permanent molars: a review and report of two cases with a new biomaterial

INTRODUCTION

Revascularization is a valuable treatment in immature necrotic teeth that allows the continuation of root development. In this article we describe successful revascularization treatment of 2 necrotic immature first mandibular molars.

METHODS

The clinical and radiographic examinations showed extensive coronal caries, immature roots, and periapical radiolucencies in mandibular first molars of a 9-year-old boy and an 8-year-old girl. The exam findings suggested revascularization treatment in both cases, which was started with irrigation of the canals by using NaOCl 5.25% for 20 minutes, followed by 3 weeks of triple antibiotic (metronidazole, ciprofloxacin, and minocycline) paste dressing. Next, the antibiotic paste was removed, bleeding was induced in the canals, and calcium enriched mixture (CEM) cement was placed over blood clots.

RESULTS

In radiographic and clinical follow-ups both cases were asymptomatic and functional, periapical radiolucencies were healed, and roots continued to develop.

CONCLUSIONS

Revascularization is a realistic treatment in immature necrotic molars. In addition, placing CEM cement as a new endodontic biomaterial over the blood clot formed inside the canals provided good seal and favorable outcomes.

Apexogenesis treatment with a new endodontic cement: a case report

INTRODUCTION

This article describes an apexogenesis report of an 8-year old boy referred to our clinic 4 weeks after an impact trauma to the maxillary left central incisor that caused a complicated crown fracture and pulpal exposure.

METHODS

In the radiographic examination, the tooth was observed to be immature. After access cavity preparation, cervical pulpotomy was performed, and the remaining pulp was capped with calcium enriched mixture (CEM) cement. The crown was restored by using the fractured incisal segment on the next day.

RESULTS

The radiographic and clinical examinations on the 6-month and 12-month follow-ups showed that the tooth remained functional, root development was completed, and the apex was formed. A calcified bridge was produced underneath the capping material. No further endodontic intervention was necessary.

CONCLUSIONS

Considering the healing potential of traumatized immature vital pulp, the use of CEM cement for apexogenesis might be an applicable choice; however, further clinical studies with longer follow-up periods are recommended.