Research and Publications

     

       

Regenerative endodontic treatment or mineral trioxide aggregate apical plug in 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 review and Meta analyses provide us with 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 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 with 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 for 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 articles shows 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 cements might be a real alternative to tooth extraction if 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 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 outcome due to either extensive damage to the periodontal tissues or inability to stop the resorption. This article presents 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 loose 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 but 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 short comings 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 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 Sherril Ann Siegel Memorial Endodontic Research Award from University of Maryland Baltimore. Calcium silicate-based cements like MTA are being widely used in Dentistry. They are bioactive and produce Hydroxyapatite in contact with moisture. This is a very important characteristic which makes them biocompatible and gives several other features like sealing ability, hard tissue induction potential, etc. Biodentine is a relatively new material which has several clinical advantages compared to the old cements like MTA. However, the data regarding how the material will work in our body is limited. This study documents the bioactivity of Biodentine in an environment similar to human body for the first time. The results showed that although Biodentin sets much faster than MTA but its bioactivity is not as great as MTA and this may cause issues in clinical situations overtime. Future studies should focus on the long term outcome of these new bioactive cements.

 

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 failure of the 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 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 “middle mesial canal” which most of the time being 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, residual infection has a detrimental effect on the outcome of regenerative treatments. This paper highlights the gaps between those researches 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 the 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 Laser is used with high power or for a long time (more than 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 a 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 a 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 molar 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 approached being tested in laboratories, animals or human. This paper is an invited review which summarizes the outcome of research in this field done till the end of 2013.

 

A preliminary report on 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 tooth by doing a vital pulp therapy instead of root canal treatment. This type of treatment is mainly done for 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 the 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 the 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 regenerate 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 of failure of pulp regeneration, root maturation 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-cements are 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 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 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 suing 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 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 failure of the treatment. This paper reviews all these issues to make 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 which also reports a case with unfavorable outcome. The review part documents all technical issues with this new treatment, gives clinical recommendations on how 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 and 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 to be successful overtime, 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 with 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 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 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 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. 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 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 the 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 patient’s symptom 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 treatment of this case was the time spent between trauma and the treatment which was 4 weeks. Successful outcome of this case showed that the healing potential of the pulp tissue might be beyond of 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 histomorphometrics 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.