Bioactivity of endodontic biomaterials on dental pulp stem cells through dentin

OBJECTIVES: This study investigated the indirect effect of calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA), as 2 calcium silicate-based hydraulic cements, on human dental pulp stem cells (hDPSCs) through different dentin thicknesses.MATERIALS AND METHODS: Two-chamber setups were designed to simulate indirect pulp capping (IPC). Human molars were sectioned to obtain 0.1-, 0.3-, and 0.5-mm-thick dentin discs, which were placed between the 2 chambers to simulate an IPC procedure. Then, MTA and CEM were applied on one side of the discs, while hDPSCs were cultured on the other side. After 2 weeks of incubation, the cells were removed, and cell proliferation, morphology, and attachment to the discs were evaluated under scanning electron microscopy (SEM). Energy-dispersive X-ray (EDXA) spectroscopy was performed for elemental analysis. Alkaline phosphatase (ALP) activity was assessed quantitatively. The data were analyzed using the Kruskal-Wallis and Mann-Whitney tests.RESULTS: SEM micrographs revealed elongated cells, collagen fibers, and calcified nucleations in all samples. EDXA verified that the calcified nucleations consisted of calcium phosphate. The largest calcifications were seen in the 0.1-mm-thick dentin subgroups. There was no significant difference in ALP activity across the CEM subgroups; however, ALP activity was significantly lower in the 0.1-mm-thick dentin subgroup than in the other MTA subgroups (p < 0.05).CONCLUSIONS: The employed capping biomaterials exerted biological activity on hDPSCs, as shown by cell proliferation, morphology, and attachment and calcific precipitations, through 0.1- to 0.5-mm-thick layers of dentin. In IPC, the bioactivity of these endodontic biomaterials is probably beneficial.

Bioactivity of endodontic biomaterials on dental pulp stem cells through dentin

OBJECTIVES@#This study investigated the indirect effect of calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA), as 2 calcium silicate-based hydraulic cements, on human dental pulp stem cells (hDPSCs) through different dentin thicknesses.@*MATERIALS AND METHODS@#Two-chamber setups were designed to simulate indirect pulp capping (IPC). Human molars were sectioned to obtain 0.1-, 0.3-, and 0.5-mm-thick dentin discs, which were placed between the 2 chambers to simulate an IPC procedure. Then, MTA and CEM were applied on one side of the discs, while hDPSCs were cultured on the other side. After 2 weeks of incubation, the cells were removed, and cell proliferation, morphology, and attachment to the discs were evaluated under scanning electron microscopy (SEM). Energy-dispersive X-ray (EDXA) spectroscopy was performed for elemental analysis. Alkaline phosphatase (ALP) activity was assessed quantitatively. The data were analyzed using the Kruskal-Wallis and Mann-Whitney tests.@*RESULTS@#SEM micrographs revealed elongated cells, collagen fibers, and calcified nucleations in all samples. EDXA verified that the calcified nucleations consisted of calcium phosphate. The largest calcifications were seen in the 0.1-mm-thick dentin subgroups. There was no significant difference in ALP activity across the CEM subgroups; however, ALP activity was significantly lower in the 0.1-mm-thick dentin subgroup than in the other MTA subgroups (p < 0.05).@*CONCLUSIONS@#The employed capping biomaterials exerted biological activity on hDPSCs, as shown by cell proliferation, morphology, and attachment and calcific precipitations, through 0.1- to 0.5-mm-thick layers of dentin. In IPC, the bioactivity of these endodontic biomaterials is probably beneficial.

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.

Triple antibiotic paste: momentous roles and applications in endodontics: a review

This study investigated the latest findings and notions regarding ‘triple antibiotic paste’ (TAP) and its applications in dentistry, particularly endodontics. TAP is a combination of 3 antibiotics, ciprofloxacin, metronidazole, and minocycline. Despite the problems and pitfalls research pertaining to this paste has unveiled, it has been vastly used in endodontic treatments. The paste's applications vary, from vital pulp therapy to the recently introduced regeneration and revascularisation protocol. Studies have shown that the paste can eliminate the root canal microorganisms and prepare an appropriate matrix for further treatments. This combination is able to remove diverse groups of obligate and facultative gram-positive and gram-negative bacteria, providing an environment for healing. In regeneration protocol cases, this allows the development, disinfection, and possible sterilization of the root canal system, so that new tissue can infiltrate and grow into the radicular area. Moreover, TAP is capable of creating a discipline in which other wanted and needed treatments can be successfully performed. In conclusion, TAP, as an antibacterial intracanal medication, has diverse uses. Nevertheless, despite its positive effects, the paste has shown drawbacks. Further research concerning the combined paste and other intracanal medications to control microbiota is a must.

Management of failed periodontal surgical intervention for a furcal lesion with a nonsurgical endodontic approach

As long as the prognosis of teeth remains a matter of concern, the endodontic-periodontal relationship will be considered a challenge for the clinician. Many etiologic factors, including bacteria, fungi, and viruses, plus other contributing factors, such as trauma, root resorptions/perforations, and dental malformations, play a role in the co-occurrence of endodontic and periodontal lesions. Whatever the cause, a correct diagnosis on which to base the treatment plan is the key to successful maintenance of the tooth. This article reports the successful endodontic management of a furcation lesion in a mandibular molar that was nonresponsive to a previous periodontal surgical graft. The case had presented a diagnostic challenge for the clinicians, and this article reviews the key points that can lead to a correct diagnosis and treatment planning.

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.

Analysis of longitudinal binary outcomes in clinical trials with low percentage of missing values

In interventional or observational longitudinal studies, the issue of missing values is one of the main concepts that should be investigated. The researcher's main concerns are the impact of missing data on the final results of the study and the appropriate methods that missing values should be handled. Regarding the role and the scale of the variable that missing values have been occurred and the structure of missing values, different methods for analysis have been presented. In this article, the impact of missing values on a binary response variable, in a longitudinal clinical trial with three follow up sessions has been investigated Propensity Score, Predictive Model Based and Mahalanobis imputation strategies with complete case and available data methods have been used for dealing with missing values in the mentioned study. Three models; Random intercept, Marginal GEE and Marginalized Random effects models were implemented to evaluate the effect of covariates. The percentage of missing responses in each of the treatment groups, throughout the course of the study, differs from 6.8 to 14.1. Although, the estimate of variance component in random intercept and marginalized random effect models were highly significant [p <0.001] the same results were obtained for the effect of independent variables on the response variable with different imputation strategies. In our study according to the low missing percentage, there were no considerable differences between different methods that were used for handling missing data

Necrosis of intact premolar caused by an adjacent apical infection: a case report

Although periapical inflammatory lesions are usually resulted by infection in the root canal system, this rare case showed that a periapical lesion related to an infected tooth may cause pulpal necrosis in adjacent intact tooth, with no history or clinical signs of caries, disease, trauma or developmental anomaly. This case also suggests that the periapical lesion can be treated conservatively, without surgical intervention. Furthermore, this case highlights the importance of prompt treatment of apical periodontitis before the lesion becomes extensive as well as follows up of large lesions.

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.

Published endodontic articles in PubMed-indexed journals from Iran

The aim of this survey was to illustrate statistical information about endodontic research published in pubmed index journals from the different universities of Iran. A PubMed search was performed to retrieve the endodontic publications of authors affiliated to different universities of Iran. Abstracts were reviewed and unrelated articles were omitted. Citation of each article was obtained from Scopus and Google scholar databases. Data were extracted and transferred to Microsoft Excel to determine the related scintometric indicators. A total of 307 papers were found according to the defined criteria which shows considerable increase from 2 papers in 1992 to 54 in 2011. The majority of the papers [48%] were related to in vitro studies; this number was 33% for in vivo surveys. Meta-analysis, systematic review and clinical trial constituted 10% of all publications. The average number of authors for the overall publications was 3.84; majority of articles [20%] were written by three authors. The average number of citation from Google Scholar [8.93] was higher than those from Scopus [4.74]. Most of the endodontic articles originated from the Mashad University of Medical Sciences [16%]. Endodontic publication from different universities in Iran has considerably increased, showing that research is becoming more important

Microleakage comparison of four dental materials as intra-orifice barriers in endodontically treated teeth

The aim of this in vitro study was to compare polymicrobial microleakage of calcium enriched mixture [CEM] cement, mineral trioxide aggregate [MTA], amalgam, and composite resin as intra-orifice sealing materials. Seventy single-rooted mandibular premolars were instrumented and obturated by cold lateral compaction technique. The teeth were randomly divided into four experimental groups according to used material: CEM, MTA, amalgam and composite resin [n=15] and two control groups [n=5]. In experimental groups, 2 mm of coronal gutta-percha was removed and replaced with the study material. All the teeth were mounted in a two-chamber apparatus and the coronal portion was exposed to human saliva. The day the turbidity occurred was recorded for each sample. Data were analyzed using one-way ANOVA. The negative control group showed no leakage while the average microleakage time in the positive control group was 3.5 days. The average bacterial leakage times for amalgam, composite resin, MTA, and CEM groups were 27.42 +/- 3.6, 29.35 +/- 3.15, 52.57 +/- 2.87, and 50.42 +/- 2.73 days, respectively. There was no significant difference between CEM and MTA groups [P=0.27] and also between amalgam and composite resin groups [P=0.36]. However, in term of average leakage time, MTA and CEM groups exhibited significant differences with amalgam and composite resin groups [P<0.001]. According to the results of the present in vitro study, in terms of coronal sealing in endodontically treated teeth, CEM and MTA are more effective than amalgam and composite resin

scientometric study of pubmed-indexed endodontic articles: a comparison between Iran and other regional countries

Based on Iran's 20-year prospective national vision document, Iran may be seen as the most developed country in science and technology in the region by 2025. In this report, bibliometric indicators are used to compare the research productivity in endodontics between Iran and 28 selected Asian countries. Medical Subject Headings keyword-searching of PubMed up to 2012 was conducted to compare the scientific publications in Iran and neighboring countries [Middle East, Middle Asia, Caucasus and EMRO countries]. Highest 5 PubMed-indexed endodontic journals were also searched to retrieve the number of published articles of the top five countries. Data were extracted, tabulated and compared to identify the ranks as well as trends. The results confirm that there are many differences in scientific endodontic publications between the studied countries; Iran ranked second in endodontic research productivity compared to Turkey in 2011. However, Iran attained first place in 2010 as well as the most positive publication trend in PubMed-indexed endodontic journals. Although Iran was in second rank in the region last year, the positive trend in published endodontic research papers is considered a sign of future success in acquiring Iran's vision

Comparing the effects of mineral trioxide aggregate and calcium enriched mixture on neuronal cells using an electrophysiological approach

The main goal of this ex vivo study was to assess and compare the cellular and electrophysiological effects of two dental biomaterials, white mineral trioxide aggregate [WMTA] and calcium enriched mixture [CEM] cement, on neuronal cell excitability and electrical properties. A conventional intracellular current clamp technique was used to study the cellular effects of WMTA and CEM on the excitability, firing and the shape of action potential of neuronal soma membrane of F1 nerve cells. The dental biomaterials were prepared according to the manufacturers' directions and were applied to the bathing media and 0.05 mL of total mixture of each dental material at a distance of 3 mm from the cells. Findings indicated that exposure to both dental biomaterials shifted the irregular high frequency firing type observed in control conditions to a more regular low frequency firing pattern. Neuronal exposure to WMTA, but not CEM, significantly hyperpolarized the cell resting membrane potential. Both treatments significantly influenced the duration and the amplitude of action potentials. Extracellular application of either CEM or WMTA caused a significant increase in the after hyperpolarization [AHP] amplitude and AHP area, but the potentiating effect of WMTA was more effective than CEM. Treatment with WMTA or CEM resulted in a profound alteration in the firing behaviour of F1 cells and changed the AP characteristics. Both dental biomaterials reduced the neuronal activity possibly through enhancement of K[+] outward current. This may possibly explain the positive mechanisms of these biomaterials in regenerative endodontics, though further research is needed for such a conclusion

One-visit RCT of maxillary incisors with extensive inflammatory root resorption and periradicular lesions: a case report

Inflammatory external root resorption [IERR] is a pathological phenomenon of microbial origin. This study reports a case of external apical inflammatory root resorption of maxillary incisors associated with periradicular lesions in a 22 year old female, which was successfully treated by one-visit root canal therapy [RCT]. Radiographic investigation revealed periapical radiolucencies in the upper incisors associated with varying degrees of external inflammatory root resorption of teeth 12, 21 and 22. One-visit RCT of all involved teeth was carried out. Access cavities were permanently restored after 1 week. Clinical and radiographic examinations at 1 day, 1 week and 14 month follow-up demonstrated complete resolution of patient's signs/symptoms. The incisors were fully functional, and complete bone healing of the apical radiolucencies had taken place. The treatment outcomes demonstrated that IERR associated with periradicular lesions can respond successfully to one-visit RCT when conducted with adequate disinfection and a satisfactory coronal seal. Hence, one-visit RCT may be a good alternative to multiple-visit RCT involving intra-canal medicaments

Management of a hopeless mandibular molar: a case report

Intentional tooth reimplantation can be an alternative treatment option for teeth with poor or hopeless prognosis where coronal and surgical endodontic treatment [s] are not possible. This technique may help to restore a natural tooth to function in preference to prosthesis/implant replacements. A 38-years old male was referred to private practice with persistent chronic apical periodontitis of a previously root canal treated mandibular left first molar. A furcal perforation and distolingual cusp fracture was previously repaired and treated with amalgam [5 years ago]. In view of the patient/tooth's limitations, intentional reimplantation was planned using CEM cement retrograde filling. Clinical and radiographic follow-up during 2 years postoperatively revealed no sign/symptoms of infection or inflammation. Moreover, periradicular healing was evident on radiographs

Periapical status and quality of root canal fillings and coronal restorations in Iranian population

This cross-sectional survey determined the dental prevalence of apical periodontitis [AP] in selected Iranian population, and evaluated the influence of the quality of root canal treatment [RCT] and their coronal restorations [CR] on the periapical status. A total of 1064 panoramic radiographies were evaluated by two observers during 2009. The quality of RCT i.e. length/density of root fillings and CR in addition to periapical status of endodontically treated teeth were recorded. Their interrelationship was analyzed by Chi-squared, logistic regression and Spearman's rho statistics. Hosmer and Lemeshow tests were used for assessing fitness of logistic regression model and one sample k-s test was used for evaluating of normality of the data. Our results showed that 527 teeth [52%] of the endodontically treated teeth presented with AP radiographically. The percentages of teeth which fulfilled the criteria of an acceptable RCT or CR radiographically were 42.3 and 62.5 respectively. Incidence of AP among teeth with acceptable RCT [29.1%] was significantly lower than those suffering from unacceptable RCT [68.8%] [P<0.001]. Moreover, adequate CR demonstrated a significantly better periapical status [58.6%] compared to teeth with inadequate CR [30.3%] [P<0.001]. The incidence of AP ranged from 25.6% [good qualities] to 79.5% [bad qualities] [P<0.001]. Cases with both unacceptable RCT/CR were 11 times more likely to have AP than cases with acceptable RCT/CR. The quality of RCT and CR were found to impact the periapical health of endodontically treated teeth. There are a significant high number of technically unacceptable endodontic and restorative treatments in Iran; therefore considerable efforts are needed to improve the standards of endodontic and restorative treatments

Comparison of bacterial and dye microleakage of different root-end filling materials

The provision of an effective apical seal is an essential factor when choosing an appropriate material for success of root-end surgeries. Root-end resection, preparation and obturation should provide an adequate apical seal. The aim of this in vitro study was to investigate bacterial and dye microleakage of four different root-end filling materials and compare the efficacy of these two methods. Fifty-six single-rooted teeth with intact and straight roots were randomly assigned into four study groups of 12 each and two control groups of three each. After decoronation, root canals were prepared up to file size #40 using step back technique; then, they were filled with gutta-percha and AH26 sealer. Root-ends were resected 3 mm above the root-end and 3 mm deep cavities were prepared. Root-end cavities were filled with amalgam, Root Mineral Trioxide Aggregate [Root MTA], White ProRoot MTA [WMTA], and calcium enriched mixture [CEM] cement. Bacterial leakage was investigated in Trypticase Soy Broth [containing Enterococcus faecalis] after 70 days and 1% methylene blue dye leakage was assessed after 72 hours. Complete dye leakage was checked using stereomicroscope [[x]40]. Data were statistically analyzed using Fisher Exact test. For pair comparison between the two methods Kapa agreement was utilized. After 70 days there was 100% bacterial leakage in amalgam, and CEM cement, 91.7% in WMTA, and 75% in Root MTA. This difference was not significantly different. The difference in complete dye leakage was also not significant [WMTA and CEM cement 16.7%, Amalgam and Root MTA 33.3%]. There was no significant measure of agreement between dye and bacterial penetration along root-end fillings. CEM cement was not significantly different from currently used retrofilling materials e.g. WMTA

Direct pulp-capping with calcium enriched mixture in primary molar teeth: a randomized clinical trial

The aim of this trial was to compare clinical and radiographic success rates of direct pulp capping [DPC] using a novel biomaterial called Calcium Enriched Mixture [CEM] cement versus Mineral Trioxide Aggregate [MTA] in primary molar teeth. In this randomized clinical trial 42 deciduous molars in 21 patients who had at least two teeth requiring DPC, were treated. The enrolled patients were between 5-8 years. The molar teeth were randomly divided into two experimental groups. Patients and operators were blinded. The teeth were anaesthetized, caries were removed and after pinpoint exposure of dental pulp, haemostasis was achieved. The exposure points were capped with MTA or CEM cement. All teeth were restored with amalgam. Patients were recalled for the 6-month follow up. Statistical analysis was carried out using McNemar test. Thirty-eight teeth were available for follow up [19 in each group]. The radiographic evaluations did not show failure in experimental groups; however, in clinical examinations one sinus tract was found in CEM cement group. Clinical success rates in CEM cement and MTA groups were 94.8% and 100%, respectively. Dentinal bridge formation was not observed in the two experimental groups. There is no significant difference between treatment outcomes of direct pulp capping with either CEM cement or MTA; therefore, both biomaterials can be used successfully for DPC in primary molar teeth

Sealing ability of MTA and CEM cement as root-end fillings of human teeth in dry, saliva or blood-contaminated conditions

Sealing ability is an important factor for a root-end filling material in endodontic surgeries. This in vitro study aimed to compare the sealing ability of mineral trioxide aggregate [MTA] and a new endodontic cement named calcium enriched mixture [CEM] cement as root-end filling materials. The experiments were carried out in dry, saliva or blood contaminated root-end cavities of hundred single-rooted extracted human teeth. After decoronation, the root canals were cleaned, shaped, obturated, and stored in 100% humidity for 5 days. Removing the apical 2-3mm of each root, a 3mm deep root-end cavity was ultrasonically prepared. Samples were randomly divided into 2 test groups of 45 roots/experimental material, and one subgroup [n=15] for each environmental condition as follows; a] dried before placing the filling material, b] filled after contamination with saliva, and c] filled after contamination with blood. Ten roots were used as positive/negative controls. Samples were placed in an incubator at 37°C for a day and immersed in methylene blue dye under reduced pressure environment for 48hours. Roots were sectioned longitudinally and examined under stereomicroscope by an independent observer. Using Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction, the results demonstrated significantly less leakage for the CEM cement in saliva contaminated condition when compared to MTA [P<0.001]. It can be concluded that the sealing ability of CEM cement was superior to MTA in saliva contaminated condition

Coronal and apical sealing ability of a new endodontic cement

This in vitro study aims to evaluate the coronal and apical sealing ability of gutta-percha [GP] root filling used with either mineral trioxide aggregate [MTA], new endodontic cement [NEC] or AH26 as filler/sealers. Forty eight single-rooted extracted teeth were selected, decoronated and then instrumented. Samples were randomly divided into three experimental [n=12] and two control groups [n=6]. In group 1, root canals were filled using lateral condensation technique [L]; while single cone technique [S] was used for groups 2 and 3. AH26, MTA and NEC were the root canal sealer/fillers in groups 1, 2 and 3, respectively. Samples were immersed in 1% methylene-blue dye and then independently centrifuged apically and coronally. The roots were split longitudinally and linear extent of dye penetration was measured with a stereomicroscope from apical and coronal directions. Data were analyzed using One-way ANOVA and T-test. No statistical differences in mean apical dye penetration between groups LGP/AH26, SGP/MTA and SGP/NEC were found; SGP/NEC group showed significantly less coronal dye penetration [P<0.001]. Considering the limitations of this in vitro study, it was concluded that the simple single cone technique with NEC can provide favorable coronal and apical seal