Research and Publications


Dr. Prashant Verma and Dr. Ali Nosrat are on faculty at the University of Maryland School of Dentistry, Division of Endodontics. They maintain an active research collaboration. Please click the links below to view our peer-reviewed publications.


Was the COVID-19 Pandemic Associated with an Increased Rate of Cracked Teeth?

Nosrat A., You P., Verma P.Dianat O., Wu D., Fouad A.F.

There is lack of data on whether the COVID-19 pandemic was associated with changes in the etiology of pathosis in patients in need of endodontic treatments. This study was aimed to determine the rate of cracks and all other etiologic factors during March-16 to May-31 in 2020 (COVID-19 outbreak) and in 2021 (COVID-19 pandemic), compared to figures from the same period in 2019 (normal pre-COVID-era) in two endodontists’ practices. Statistical analyses on the records of 2444 teeth showed that there was a significant increase in the rate of cracked teeth during the COVID-19 outbreak in 2020. The rate of cracked teeth later reduced in 2021 during the COVID-19 pandemic but it did not return to its normal levels in 2019. Patients aged 40-60 had a higher rate of cracked teeth during the pandemic as compared to other age groups. This study was published in the Journal of Endodontics issue of October 2022 and was highlighted on the cover of the issue. 


Endodontic Specialists’ Practice During the Coronavirus Disease 2019 Pandemic One Year after the Initial Outbreak

Nosrat A., Yu P., Dianat O., Verma P., Taheri S., Wu D., Fouad A.F.

Journal of Endodontics 2022; 48(6): 699-706

The aim of this study was to determine how the ongoing COVID-19 pandemic 2021 changed the characteristics of patients in need of endodontic treatments. The study also aimed to determine whether the dramatic changes observed during the outbreak of COVID-19 in 2020 were reversed in 2021. Demographic, diagnostic, and procedural data of 2657 patient visits, from March-16 to May-31 in 2019, 2020, and 2021 were collected and analyzed. Patients’ self-reported pain levels and number of visits with irreversible pulpitis in 2021 were higher than 2019. Patient’s self-reported pain, percussion pain, and palpation pain levels in 2021were less than 2020.  Ongoing COVID-19 pandemic in 2021 was associated with an increase in the number of non-surgical root canal treatments. Some of the changes observed during the initial outbreak in 2020, including objective pain parameters, returned to normal levels one year later.
This study was published in the Journal of Endodontics issue of June 2022 and was highlighted on the cover of the issue. 


Regenerative endodontic treatment using periapical blood or circulating blood as scaffold: a volumetric analysis

Alghofaily M., Torabinejad M., Nosrat A.

Journal of Endodontics. 2022; 48(5): 625-631

Difficulty in obtaining adequate bleeding from the periapical tissue to form a blood clot is one of the potential challenges encountered during regenerative endodontic procedures. This is the first study exploring the possibility of using peripheral circulating blood instead of periapical blood as a scaffold for tissue regeneration. Immature vital teeth in a sheep model received single-visit regenerative endodontic treatment after pulpal debridement. Continued root development was evaluated using micro-CT images after the procedure. The group that received circulating blood and the group that received periapical blood showed similar degrees of continued root development, as reflected in the incidence of apical closure, root length, and wall thickness, as well as root volume. These results suggest that circulating blood can be used as an alternative to periapical blood as a scaffold for regenerative endodontic treatment. 


Endodontic specialists’ practice during the initial outbreak of COVID-19

Nosrat A., Dianat O., Verma P., Yu P., Wu D., Fouad A.F.   

Journal of Endodontics. 2021; 48(1) 102-108

The first outbreak of coronavirus disease 2019 (COVID-19)   in the United States resulted in 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 Centreville Endodontics and Capitol Endodontics from March-16 to May-31, 2020, compared to the same period in 2019. Demographic, diagnostic, and procedural data of 1520 (693 in 2020; 827 in 2019) patient visits were collected. We then ran a series of sophisticated statistical analyses to determine the effect of COVID-19 outbreak on patients. The analyses showed that patients seen during the initial outbreak of COVID-19 presented with higher levels of pain, higher frequency of acute dental abscesses, and received more incision for drainage. COVID-19 outbreak was significantly associated with less visits for patients older in age, more patients with kidney diseases, higher levels of pain on percussion, and higher number of root canal treatments and root-end surgeries. In this study we showed for the first time that the public health burden of tooth infections was more intense during the initial outbreak of COVID-19 in the United States. 


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

Nosrat A., Bolhari B., Saber Tahan S., Dianat O., Dummer P.M.H.

International Endodontic Journal. 2021

Regenerative endodontic procedures were introduced for the treatment of immature teeth with primary endodontic infection. However, over time clinicians tried modifications of this technique in previously root canal treated teeth and achieved successful outcomes. This means that there is an option to revitalize a previously root canal-treated tooth that has an open apex. Revitalizing the root canals of previously treated teeth with open apices is appealing to both 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. This study is the first review of the baseline, procedural and outcome data of previously treated teeth retreated and revitalized using regenerative endodontic treatments. The authors of the study also designed an assessment tool for case report studies and applied it to case reports included in this study. This assessment process showed most case reports in this field had a “fair” quality of evidence.


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

Dianat O.Nosrat A., Mostoufi B., Price J.B., Gupta S., Martinho F.C.

International Endodontic Journal. 2021

When a root canal treatment fails one treatment option is root-end surgery. During this surgery, the clinician should be able to conservatively navigate a path to the infected root apex. Targeting the root apex during root-end surgeries can be a challenging task specifically if the root apices are far from the cortical plate. Dynamic Navigation System (DNS) is a new technology introduced to the field of dentistry to primarily help clinicians to navigate the path of drilling for dental implants. The system’s software uses cone computed tomography (CBCT) images to design a path of drilling for surgeons. The technique used in this system is a dynamic method, meaning that the clinician looks at a screen in front of them (instead of the patient’s mouth) where they can see the virtual path to the target point. In this research study, we examined the performance of DNS for a guided root-end resection on human cadaver teeth for the first time. We compared the linear and angular deviation of the drilling as well as the time of operation using DNS compared to a freehand technique done under microscope magnification. The data from this study showed significantly higher accuracy and efficiency in the DNS group. The data also showed that, unlike the DNS group, in the freehand group the accuracy and efficiency (i.e. time of operation) of the clinician was negatively associated with the distance of the root apex from the cortical plate.    


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

Nosrat A., Verma P., Glass S., Vigliante C. E., Price J.B.

Journal of Endodontics. 2021; 47(4): 671-676

Misdiagnosis of malignant radiolucent lesions is a crucial mistake because these lesions can mimic endodontic infections. A misdiagnosis delays receiving the appropriate medical treatment, which can be catastrophic. In this case report paper, for the first time, we used CBCT images to segment and print a 3D model of non-Hodgkin lymphoma in the maxilla. CBCT imaging is a technology available in many general dentist and endodontist offices and the images can be easily used to prepare a 3D model of a bony lesion. This methodology can be useful in assessing, diagnosing, and treatment planning for surgical removal of a malignant lesion in the bone. In this case, the 3D printed models of the tumor allowed for a realistic and crucial evaluation of the tumor’s location and size. This information can also provide a baseline radiographic reference in case of tumor recurrence.


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

Nosrat A., Dianat O., Verma P., Nixdorf D.R., Law A.S.

Journal of Endodontics. 2021; 47(3): 358-365

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 the quality of life. In this research project, we examined the research variables of 424 articles published on postoperative pain in the field of endodontics published since 1970. We then performed a “trend analysis” to discover trends of research in the past five decades. The trend analysis quantifies and explains trends and patterns in noisy data over time. The analyses showed that there is still a significant need for studies with large sample sizes and a long duration of follow-up. We also discovered that there has been a lack of focus on clinical conditions that are more prone to postoperative pain, mainly teeth with pulp necrosis and teeth with failed root canal treatment. We recommended a paradigm shift in research studies regarding these variables to generate more clinically relevant data.  


Accuracy and Efficiency of a Dynamic Navigation System for Locating Calcified Canals

Dianat O.Nosrat A., Tordik P.A., Aldahmash S.A., Romberg E., Price J.B., Mostoufi B.
Journal of Endodontics. 2020; 46(11): 1719-1725

Dynamic Navigation System (DNS) is a new technology introduced to the field of dentistry to primarily help clinicians to navigate the path of drilling for dental implants. The system’s software uses cone computed tomography (CBCT) images to design a path of drilling for the surgeon. The technique used in this system is a dynamic method, meaning that the clinician looks at a screen in front of them (instead of the patient’s mouth) where they can see the virtual path to the target point. If the clinician deviates from the path or starts drilling at a wrong spot the system stops and does not allow to continue. The novel technology has potential for use in the field of endodontics where a projected approach towards a target is always a clinical challenge. Calcified canals are one of the clinical challenges that endodontists deal with in their daily practice. In this research project, we used the DNS to locate calcified canals in human teeth for the first time. We compared the linear and angular deviations of the drilling path as well as the time of operation (i.e., efficiency) to a freehand technique done under microscope magnification. The data showed that DNS had a significantly less linear and angular deviation when compared with the freehand technique under a microscope. DNS was significantly more efficient than the freehand technique.

Alexander A., Torabinejad M., Vahdati S.A., Nosrat A., Verma P., Gandhi A., Shabahang S.

Journal of Endodontics, 2020;46(2): 209-21

The research on scaffolds used in Regenerative Endodontic Treatments (RET) is an evolving field. A new collagen hydroxyl-apatite-based scaffold called SynOss was introduced for use in RET. Our group published previous reports on the successful use of SynOss in human teeth. The present research study was designed to test SynOss in ferrets to understand the differences between SynOss and blood clots, a common scaffold used in RET. This study showed a lack of tissue formation in most teeth where SynOss was used as a scaffold. We concluded that the ferret model was not the right model to test this new scaffold. Further studies using different animal models were suggested to evaluate and compare the histological outcome of RET using SynOss compared to a blood clot. 


Regenerative endodontic treatment as a biologically based approach for non-surgical retreatment of immature teeth

Cymerman J.J., Nosrat A.

Journal of Endodontics, 2020;46(1): 44-50

There is no consensus in using regenerative endodontic treatments (RET) in teeth with previous root canal treatment. This article documents the long-term outcome of RET in previously treated immature teeth. In order to make the outcome stable and predictable, the authors used a novel collagen-hydroxyapatite-based matrix, SynOss, mixed with blood as a scaffold. The cases were followed up for up to 6 years. The follow-ups were done using 2D and 3D imaging technology. The successful outcome of these cases showed that RET can be a viable treatment option in immature teeth with failed root canal treatment. This article added a new perspective to the field of regenerative endodontics.


Vital pulp therapy as a conservative approach for management of invasive cervical root resorption: A case series

Asgary S., Nourzadeh M., Verma P., Hicks M.L., Nosrat A.

Journal of Endodontics, 2019;45(9): 1161-1167

Invasive Cervical Root Resorption (ICRR) presents a clinical dilemma and challenge to endodontic clinicians. It is a dilemma because the exact etiology of this pathologic condition is not known. The most common conditions associated with this resorption are the history of trauma and orthodontic treatments. It is a challenge because a definitive treatment protocol with a predictable outcome is not discovered yet. Pulp tissue remains normal in most cases with ICRR. Thus, an internal excavation of the resorption and vital pulp therapy (VPT) can preserve the periodontium as well as the vitality of the tooth. In this article, six molar teeth diagnosed with ICRR were treated with internal excavation and different VPT techniques. All teeth were clinically and radiographically successful during recalls. The outcome of this case series article presented a novel and conservative approach for the treatment of ICRR. 


Regenerative Endodontics: A Scientometric and Bibliometric Analysis

Shamszadeh S., Asgary S., Nosrat A.

Journal of Endodontics, 2019;45(3): 272-280

Scientometric analyses are done to determine the level of evidence, the quantity and quality of publications, and the major players (Authors, Journals, Countries) in a scientific field. Scientometric analyses are common in the field of medicine, but they are rare in the field of dentistry and endodontics. This scientometric analysis showed that the total number of publications in the field of regenerative endodontics has exponentially grown over the past decade, with an average growth rate of 40.4%. The overall ratio of articles with LOE 1 is still low. A total of 1820 authors in 53 countries contributed to the research in this field. Journal of Endodontics published the highest number of papers in this field. The United States was the lead country regarding the number of publications, citations, and international collaborations. Research groups around the globe are urged to focus their collaborative efforts on higher-quality research to address clinical needs.



The clinical, radiographic, and histologic outcome of regenerative endodontic treatment in human teeth using a novel collagen-hydroxyapatite scaffold

Nosrat A., Kolahdouzan A., Khatibi A.H., Verma P., Jamshidi D., Nevins A.J., Torabinejad M.

Journal of Endodontics, 2019;45(2): 136-143

Histological examination of teeth after regenerative endodontic treatment (RET) shows that the type, quality, and quantity of tissues formed in the root canal space is not predictable. A new collagen-based scaffold, SynOss Putty, has shown promising clinical results when used in RET. However, there was no histological data on the newly formed tissues in human teeth. In this study, for the first time, we examined clinical, radiographic, and histological outcomes of RET in human teeth using SynOss Putty as a scaffold. The results showed that SynOss Putty has a unique capacity in inducing the formation of new mineralized tissue in immature human teeth following RET. This new tissue solidifies with the dentinal walls, and therefore, can increase the fracture-resistant in immature teeth. This new mineralized tissue was different from the loose connective tissue formed following the use of blood clots as a scaffold.  


Antibacterial Efficacy and Discoloration Potential of Endodontic Topical Antibiotics

AlSaeed T., Nosrat A., Melo M.A, Wang P., Romberg E., Xu H., Fouad A.F.

Journal of Endodontics, 2018;44(7):1110-1114

This ex vivo study investigated the antimicrobial efficacy and color differences for several concentrations of antibiotic/hydrogel mixtures with potential use as medicaments in regenerative endodontic therapy. The findings would guide the providers in selecting the most efficacious and least discoloring agent. The study showed that lower concentrations of antibiotics might be as antibacterial as higher concentrations without discoloration potential. This study tested the antibacterial efficacy and discoloration potential of a new antibiotic, Tigecycline, for the first time.

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

Verma P., Nosrat A., Tordik P.

Journal of Endodontics, 2018;44(6):1042-1047

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 bone, periodontium, nerves, and vasculature. This article reports on the catastrophic consequences of an accidental chloroform injection and presents a review of the published literature on accidental injections and accidental irrigations. Our goal is to disseminate information on toxicity and biocompatibility of materials/ solutions used in endodontics and to train dental students and endodontic residents on the therapeutic management of patients when an accidental injection or accidental irrigation occurs.


Regenerative endodontic treatment or mineral trioxide aggregate apical plugin teeth with necrotic pulps and open apices: a systematic review and meta-analysis

Torabinejad M., Nosrat A., Verma P., Udochukwu O.

Journal of Endodontics, 2017;43(11):1806-1820

Systematic reviews and Meta-analyses provide us with the highest level of evidence. Regenerative endodontic treatment (RET) is the hottest topic of research in the field of endodontics. In this treatment, the clinician revitalizes the necrotic immature tooth using a specific disinfection protocol and a tissue engineering strategy. This research project aimed to determine the level of evidence for RET. It also aimed to compare the outcome of RET with the outcome of the existing standard procedure, MTA apical plug (MAP), for the treatment of immature teeth with pulp necrosis.  The results showed that the level of evidence for MAP and RET was low. The pooled survival rates were 97.1% and 97.8%, for MAP and RET, respectively.  The pooled success rates were 94.6% and 91.3% for MAP and RET, respectively.  There was no significant difference between the two groups regarding survival or success rates. More high-level clinical studies (i.e., randomized clinical trials) comparing the outcome of these two treatment modalities are needed.


Variations of palatal canal morphology in maxillary molars: a case series and literature review

Nosrat A., Verma P., Hicks M.L., Schneider S.C., Behnia A., Azim A.A.

Journal of Endodontics, 2017;43(11):1888-1896

Palatals canals in maxillary molars are considered easy-to-treat for endodontic clinicians because they are larger and less curved compared to other canals. However, root canal treatment in these canals can be challenging in case of anatomical variations. This case series showed that experienced endodontic clinicians can miss a bifurcated palatal canal if they are not aware of these anatomical variations.        The review part of this paper shows that although the overall prevalence of anatomical variations in the palatal canal of maxillary molars is low (<2%), it can reach up to 33% in maxillary first molars and up to 14% in maxillary second molars in certain ethnic groups (i.e., Indians, Pakistanis, and Turkish).


Treatment outcomes of full pulpotomy as an alternative to tooth extraction in molars with hyperplastic/ irreversible pulpitis: a case report

Asgary S., Verma P., Nosrat A.

Iranian Endodontic Journal, 2017;12 (2): 261-265

Root canal treatments are highly successful procedures to save mature teeth diagnosed with irreversible pulpitis due to large caries. But these treatments are expensive and require a higher level of skills, specifically in molar teeth. Therefore, root canal treatment might not be a realistic option to save teeth for underserved people, people without dental insurance, or those who do not have access to highly skilled dentists. As a result, many restorable teeth are extracted every year. An alternative to root canal treatment will be a “pulpotomy” using biocompatible materials. The clinical studies on pulpotomy of mature teeth are limited. This article shows the successful outcome of pulpotomy done in two molars using a novel biomaterial, CEM cement. The 2-year follow-up is documented clinically and radiographically (2D and 3D). In conclusion, the option of pulpotomy with bioactive cement might be a real alternative to tooth extraction if a root canal is not feasible.


Effect of Residual Bacteria on the Outcome of Pulp Regeneration In Vivo.

Verma P, Nosrat A, Kim JR, Price JB, Wang P, Bair E, Xu HH, Fouad AF.

Journal of Dental Research. 2017; Jan 96(1):100-106

This project was funded by the American Association of Endodontists Foundation and published in the prestigious journal JDR, which consistently ranks #1 or #2 on the basis of impact factor among all dental journals. The purpose of the study was to determine, radiographically and histologically, the effect of residual infection on pulp regeneration procedures. It was an animal study using the ferret canine model. There were two groups- one with a novel autologous stem cell transplantation method, and the other with a traditional blood clot method for regenerative endodontics. The results of this study showed, for the first time, that residual bacteria have a critical negative effect on the outcome of regenerative endodontic procedures.


Conservative Management of Class 4 Invasive Cervical Root Resorption Using Calcium-Enriched Mixture Cement.

Asgary S, Nosrat A.

Journal of Endodontics. 2016; Aug 42(8):1291-4.

Treatment of class 4 invasive cervical resorption is a challenge. Almost all treatment approaches (surgical or non-surgical) have unfavorable outcomes due to either extensive damage to the periodontal tissues or inability to stop the resorption. This article presents the successful management of a case of class 4 invasive cervical resorption using a novel noninvasive nonsurgical approach in a young female who was about to lose her front tooth. A bioactive cement, CEM cement, was used as root canal filling material to stop the resorption and induce healing in periodontal tissues.


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

Homayounfar N, Verma P, Nosrat A, El Ayachi I, Yu Z, Romberg E, Huang GT, Fouad AF.

Journal of Endodontics. 2016; 42(3):418-24.

This project was funded by the American Association of Endodontist Foundation (AAEF). Ferret’s teeth are an appropriate model to study regenerative endodontic treatments and tissue engineering strategies for these treatments. The study aimed to examine the differentiation characteristics of ferret’s dental pulp stem cells for the first time. The results of this study showed that even though ferret dental pulp stem cells might mimic some characteristics of human dental pulp stem cells, they are different in some other aspects. These differences should be considered when running animal studies and interpreting the outcomes of those studies.


Histological Outcomes of Uninfected Human Immature Teeth Treated with Regenerative Endodontics: Two Case Reports

Nosrat A, Kolahdouzan A, Hosseini F, Mehrizi E, Verma P, Torabinejad M

Journal of Endodontics 2015; 41(10):1725-9

This study is a case report which documents the histological outcomes of regenerative endodontic treatments in non-infected human teeth for the first time. The experiment was done on teeth planned for extraction because of orthodontic treatments. This research points out the shortcomings of the current protocol published by the AAE. It also establishes an appropriate model to study the outcomes of tissue engineering strategies in human teeth. This study gave us new ideas about future studies. There are three ongoing projects designed based on this paper.


Endodontic Management of a Maxillary Lateral Incisor with Four Root Canals and a Dens Invaginatus Tract

Nosrat A, Schneider SC

Journal of Endodontics. 2015;41(7):1167-71

Clinicians need to know about the internal anatomy of the teeth in order to do an efficient root canal treatment. Maxillary lateral incisors are considered as a single-rooted tooth with a single canal. This study documents the successful treatment of a maxillary lateral incisor with five canals. Using CBCT imaging, we built a 3D image of the tooth and designed a specific approach to treat all canals in two sessions. This study not only highlights the anatomical variations in human teeth but also shows how 3D imaging can be used in Endodontics to strategize the treatment approach.


Interfacial characteristics of Biodentine and MTA with dentine in simulated body fluid.

Kim JR, Nosrat A, Fouad AF

Journal of Dentistry. 2015;43(2):241-7

This study was funded by the Sherril Ann Siegel Memorial Endodontic Research Award from the University of Maryland Baltimore. Calcium silicate-based cement-like MTA is being widely used in Dentistry. They are bioactive and produce Hydroxyapatite in contact with moisture. This is a very important characteristic that makes them biocompatible and gives several other features like sealing ability, hard tissue induction potential, etc. Biodentine is a relatively new material that has several clinical advantages compared to old cement-like MTA. However, the data regarding how the material will work in our bodies is limited. This study documents the bioactivity of Biodentine in an environment similar to the human body for the first time. The results showed that although Biodentin sets much faster than MTA its bioactivity is not as great as MTA and this may cause issues in clinical situations over time. Future studies should focus on the long-term outcome of these new bioactive cement.


Middle Mesial Canals in Mandibular Molars: Incidence and Related Factors.

Nosrat A, Deschenes RJ, Tordik PA, Hicks ML, Fouad AF.

Journal of Endodontics. 2015, 41(1):28-32

One of the major reasons for the failure of a root canal treatment is missed canals. When the clinician does not have enough knowledge about the internal anatomy of the tooth then they may miss some details which can cause the failure of the treatment. Mandibular molar teeth are the most frequently extracted teeth following root canal treatment. There is a rare canal in these teeth called the “middle mesial canal” which most of the time is overlooked during the treatment. This study documents the incidence of this particular canal in different age groups and different ethnicities. The very most important finding of this study is that the prevalence of this canal is significantly higher in younger patients (< 20 years old). Clinicians are encouraged to look for this canal when treating young patients. This paper made the cover of the Journal of Endodontics issue of January 2015.


Healing after regenerative procedures with and without pulpal infection.

Fouad AF, Verma P.

J Endod. 2014 Apr;40(4 Suppl):S58-64.

This is a review paper published as proceedings to the “Pulp Biology and Regeneration Group Meeting” held in March 2013 in San Francisco.

This paper highlights the biological aspects of regenerative endodontic treatments with a specific focus on the differences between infected and non-infected root canal spaces. As shown in other studies, the residual infection has a detrimental effect on the outcome of regenerative treatments. This paper highlights the gaps between the research done on non-infected models and the real clinical situations where the clinicians are dealing with difficult-to-remove infections in immature teeth. Pulp regeneration in previously infected teeth is still a challenge. More clinical and animal studies are needed to reach an ideal treatment protocol in this field.


Efficacy of Er,Cr:YSGG Laser in Removing Smear Layer and Debris with Two Different Output Powers.

Bolhari B, Ehsani S, Etemadi A, Shafaq M, Nosrat A

Photomed Laser Surg. 2014 Oct;32(10):527-32

New technologies have always been the subject of research in the field of endodontics. Laser radiation has several potential applications in dentistry. Laser irradiation can potentially be used as an aid to root canal irrigation to enhance the quality of debridement. In this research, we aimed to evaluate the cleaning effect of Laser irradiation on dentinal walls of the root canal space as a potential replacement for irrigation solutions. The outcomes of this project proved that Laser irradiation can potentially be a replacement for our traditional root canal irrigation in specific output powers. It also shows that if the Laser is used with high power or for a long time (more than a few seconds) it can cause irreversible damages to the dentinal walls of the root canal space.


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

Asgary S, Eghbal MJ, Mehrdad L, Kheirieh S, Nosrat A

Restor Dent Endod. 2014 May;39(2):137-42

Treatment of root resorptions is a challenge in endodontics. It takes a significant amount of knowledge and effort to determine the etiology, extension, and a successful treatment plan. In some cases, a non-surgical approach would be enough to stop the resorption, in other cases a surgical approach or a combination of both approaches is needed. This report documents a rare case of internal resorption where the initial treatment using MTA (a standard material used in these cases) was failed. The tooth was eventually saved by doing surgery using a novel bioactive cement called CEM.


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

Asgary S, Nosrat A

Gen Dent. 2014 May-Jun;62(3):30-3

When a root canal treatment fails and retreatment or a root-end surgery are not feasible one treatment option would be intentional replantation. In this procedure, we extract the tooth, fix the issues with the root canal treatment and replant the tooth and stabilize it for a short period of time. This procedure is a last resort to save the tooth. In this paper, we reported concurrent intentional replantation of two maxillary molars with failed root canal treatment. The patient did not want to go through a retreatment or a root-end surgery. There are two novel aspects related to this case: doing this procedure for two molars at the same time and using a novel bioactive cement called CEM as the root-end filling material. The successful outcome of this was documented during a two-year follow-up period.


Tissue engineering considerations in dental pulp regeneration

Nosrat A, Kim JR, Verma P, Chand P

Iranian Endodontic Journal 2014; 9: 30-39

Pulp regeneration is a hot topic for research in Endodontics. There are several different tissue engineering approaches being tested in laboratories, animals, or humans. This paper is an invited review that summarizes the outcome of research in this field done till the end of 2013.


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

Nosrat A, Peimani A, Asgary S

Restorative Dentistry and Endodontics 201; 38: 227-33

In some specific clinical situations, the endodontist might be able to save the vitality of the tooth by doing a vital pulp therapy instead of root canal treatment. This type of treatment is mainly done for a young patient whose teeth are immature and the roots are still developing. The type of materials used in vital pulp therapy plays a crucial role in the outcome of treatment. Plus, histological studies on human teeth regarding the outcome of vital pulp therapies are very rare. In this project, we evaluated the histological outcome of vital pulp therapy in human teeth with a novel endodontic biomaterial called CEM cement. We used wisdom teeth scheduled for extraction. The results of the study showed favorable results for this new biomaterial compared to the traditional material, MTA.


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

Ehsani S, Bolhari B, Etemadi A, Ghorbanzadeh A, Sabet Y, Nosrat A

Photomedicine and Laser Surgery 2013; 31: 578-85

Laser irradiation can potentially be used as an aid to root canal irrigation to enhance the quality of debridement. One way to assess this effect is to look at the quality of root canal filling after being treated by Laser. In this research project, we examined the push-out bond strength of a specific root canal filling material following Laser treatment. The results confirmed that Laser irradiation can be a valuable addition to root canal irrigation.


Is pulp regeneration necessary for root maturation?

Nosrat A, Li K, Vir K, Hicks M, Fouad A

Journal of Endodontics 2013; 39: 1291-5

This paper is a case report which proves a very important concept related to regenerative endodontic treatments. There are so many challenges to regenerating the pulp tissue in a previously infected root canal space. This paper documents a case where pulp regeneration failed, and the root canal space was empty upon reentry. This paper shows how an ideal infection control for pulp regeneration can become challenging in an immature tooth. It also shows that despite the failure of pulp regeneration, root maturation was obtained.


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

Oloomi K, Saberi E, Mokhtari H, Mokhtari Znouzi HR, Nekoofar MH, Nosrat A, Dummer P

Restorative Dentistry and Endodontics 2013, 38(3):128-33

Blood contamination can cause problems with specific materials in dentistry. Some dental materials are compatible with moisture and are designed to be used where blood contamination is a possibility. Generally, all calcium silicate cement is claimed to be moisture compatible. However, research studies show that blood contamination can affect some of their physical properties. In this project, we evaluated the compressive strength of MTA following blood contamination. The results showed that blood contamination indeed reduced the compressive strength of MTA. The clinicians were recommended to avoid blood contamination while using MTA.


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

Bolhari B, Meraji N, Nosrat A

Iranian Endodontic Journal 2013; 8(2): 72-4

Root resorptions are among the least understood dental diseases. The etiology of some of the resorptions is well known. But some others are idiopathic, meaning that the etiology is unknown. Idiopathic root resorptions represent a challenge to the dentist. Since the cause is unknown there is no specific treatment to address the cause and stop the resorption. All we can do as a researcher is to evaluate the dental and medical history of the patient in detail and try to find a correlation between a specific dental or medical status and the root resorption. When a specific dental procedure or medical status is found repeatedly in the history of patients with root resorption then we can make a correlation. This paper represents a case of extensive idiopathic root resorption evaluated using 3D imaging and radiographs. A detailed dental and medical history of the patient was represented and examined.


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

Nosrat A, Seifi A, Asgary S

International Journal of Paediatric Dentistry 2013, 23(1): 56-63

Research studies are classified based on the level of evidence they represent. Randomized clinical trials are the highest level of evidence in clinical research. Endodontic treatment in immature teeth of young patients (7-10 years old) with large caries is a challenge. The endodontist is supposed to save the vitality of the tooth instead of doing root canal treatment by doing a “vital pulp therapy”. Vital pulp therapy can be done in the form of full pulpotomy where the most inflamed part of the pulp will be removed and the rest of it will be covered with a bioactive material to allow the roots to continue developing. This study compared the results of pulpotomy using a traditional material, MTA, compared to a novel material, CEM cement. This was the first clinical trial published in this field and the paper has been highly cited all around the world.


Pulp regeneration in previously infected root canal space

Fouad A, Nosrat A

Endodontic Topics, 2013; 28:24-37

This paper is an invited review. Endodontic Topic is a yearly publication of the American Association of Endodontists (AAE) and it only publishes invited reviews. Pulp regeneration in previously infected root canals is a serious challenge. Complete disinfection of the root canal space affects the biological outcome of the regenerative procedures. On the other hand, leaving bacteria behind in the root canal space can cause the failure of the treatment. This paper reviews all these issues to make a clear picture of this challenge. It also makes recommendations for future research in this field.


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

Nosrat A, Homayounfar N, Oloomi K

Journal of Endodontics, 2012; 38(10): 1428-34.

As regenerative endodontic treatments become more popular among clinicians, they face more adverse effects and unfavorable outcomes. These situations need to be brought to the attention of the clinicians and they have to inform the patient when planning for such treatments. This paper is a review paper that also reports a case with an unfavorable outcome. The review part documents all technical issues with this new treatment gives clinical recommendations on how to avoid the adverse effects and also gives recommendations for future research. This paper has been cited frequently by other researchers in the field.


Unintentional extrusion of mineral trioxide aggregate: a report of three cases

Nosrat A, Nekoofar M, Bolhari B, Dummer P

International Endodontic Journal 2012, 45(12):1165-76.

MTA is a biocompatible material being used in dentistry for close to two decades. Numerous animal and lab studies have shown its biocompatibility. MTA can be used as root canal filling material. Due to its biocompatibility, there is a misconception that this material can be extruded beyond the apex with no consequences. Our clinical experience showed that this is true in most cases but not in all. In this paper, we reported three cases with extrusion of MTA. One case turned out to be successful over time, and the other two failed and required further treatment. As a conclusion, we recommended the clinicians to limit the MTA root canal fillings to the canal boundaries and be cautious about the overextensions of the material.


Periapical healing after direct pulp capping with calcium-enriched mixture cement: a case report.

Asgary S, Nosrat A, Homayounfar N

Operative Dentistry 2012; 37(6): 571-5

The healing potential of the pulp tissue is not very well understood. While patients at different ages can represent the same symptoms when they have pulpal diseases the treatment can differ based on their age. Direct pulp capping is a vital pulp therapy suggested for deep cavities when the patient has no symptoms. Direct pulp capping on symptomatic patients is not recommended due to the high chance of failure. We believe that patient’s age plays a crucial role in the outcome of these treatments. This paper reports a successful direct pulp capping done in a symptomatic patient. We used a novel bioactive cement called CEM cement for the treatment.


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

Nosrat A, Asgary S, Eghbal M, Ghoddusi J, Bayat-Movahed S

Journal of Conservative Dentistry 2011, 14(4): 427-31

This paper is a case series where a novel bioactive cement (CEM cement) was used as a root canal filling material in immature teeth with open apices. For decades, root canal filling of these teeth was a challenge for dentists and endodontists until MTA was introduced to dentistry. Although MTA has been successfully used for several years it is a difficult-to-use material and has some other issues like discoloration potential. CEM cement is easier to use and does not discolor teeth. We followed up on all these cases until the periapical lesions healed completely in all of them.


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

Nosrat A, Seifi A, Asgary S

Journal of Endodontics 2011; 37(4): 562-7

After regenerative endodontic treatments were introduced researchers and clinicians tried different techniques and modifications in order to improve the outcome. All the reported cases till 2011 were single-rooted teeth with a single canal (anterior teeth and some premolars). In this paper, we successfully revitalized two infected immature molar teeth for the first time by making minor changes in the treatment techniques. This paper has been highly cited by researchers and is one of the references for the Regenerative Endodontic Treatment protocol published by the American Association of Endodontists.


Management of inflammatory external root resorption by using calcium-enriched mixture cement: a case report.

Asgary S, Nosrat A, Seifi A

Journal of Endodontics 2011; 37(3):411-3

One of the serious consequences of trauma to the teeth is inflammatory root resorption. If left untreated, this type of resorption can destroy the entire root structure within a few weeks and make the tooth mobile and hopeless. This resorption is most of the time asymptomatic and can only be diagnosed by taking radiographs. The routine protocol requires the clinicians to do a long-term disinfection process using calcium hydroxide paste. The patient needs to be very cooperative and attend multiple sessions of treatment. This case report documents treatment of a case of severe inflammatory root resorption due to a traumatic injury. The patient was referred to us because of extensive root resorption and mobility. The novel aspect of the treatment we rendered is that we reduced the period of calcium hydroxide treatment and filled the canal with a new bioactive cement called CEM cement. Forty months follow-up of the case documented the favorable results for the treatment.


Apexogenesis of a symptomatic molar with a calcium-enriched mixture.

Nosrat A, Asgary S

International Endodontic Journal 2010; 43(10): 940-4

Vital pulp therapies are regularly done in asymptomatic immature teeth with deep caries. Since the healing potential of the pulp tissue is not very well understood, clinicians are encouraged to not perform vital pulp therapies in symptomatic teeth with deep caries. On the other hand, if successful, vital pulp therapy will have significant benefits for young patients. It allows further root development and can increase the longevity of the tooth. This case report describes a symptomatic permanent immature tooth with deep caries treated for the first time with CEM cement is a bioactive material. The long-term follow-up of the case shows the success of the treatment and documents root development despite the patient’s symptoms at the beginning.


Apexogenesis treatment with a new endodontic cement: a case report.

Nosrat A, Asgary S

Journal of Endodontics 2010; 36(5): 912-14

Traumatic injuries to the teeth are common among kids and young adults. These injuries can have severe consequences for the vitality of the tooth. Most of these teeth are immature and have not been developed fully and these injuries can arrest their root development. If the pulp tissue becomes exposed to the oral cavity due to a traumatic fracture clinician should clean and seal the exposed tissue as soon as possible but no later than 48 hours. This paper reports a case of traumatic fracture in an immature front tooth undergone vital pulp therapy using a novel cement, CEM cement. Another novel aspect in the treatment of this case was the time spent between trauma and the treatment which was 4 weeks. The successful outcome of this case showed that the healing potential of the pulp tissue might be beyond what we know.


Histomorphometric comparison of canals prepared by four techniques.

Baumgartner JC, Martin H, Sabala CL, Strittmatter EJ, Wildey WL, Quigley NC.

J Endod. 1992 Nov;18(11):530-4

Numerous methods of root canal preparation have been recommended and used by clinicians. This study used histomorphometric to determine the area of root canal preparations using four currently popular techniques. Clinicians that were highly skilled in each technique prepared curved canals in acrylic blocks. Each clinician described this technique and discussed the technique with regard to the use of acrylic blocks as compared with dentin. Analysis of the areas of the root canals after preparation revealed a significant difference among the groups.


Conservative treatment of persistent periradicular lesions using aspiration and irrigation.

Hoen MM, LaBounty GL, Strittmatter EJ.

J Endod. 1990 Apr;16(4):182-6.

Aspirating the unknown contents of a bony cavity and saline irrigation of a body wound are both basic surgical techniques. These two techniques have been combined in treating persistent periradicular pathosis in two cases. The cases demonstrate significant bony healing of extensive periradicular defects after the use of the combined procedure. Both cases were nonresponsive to nonsurgical root canal treatment. The use of aspiration and irrigation may initiate healing in cases of uninfected apical cysts which heretofore would require surgical intervention. The conservative nature of these procedures has advantages of reduced treatment time, avoidance of iatrogenic problems, and elimination of some conventional apical surgery.