Mohamed I. Fayad

In Vivo Generation of Dental Pulp-like Tissue by Using Dental Pulp Stem Cells, a Collagen Scaffold, and Dentin Matrix Protein 1 after Subcutaneous Transplantation in Mice

The presence of a perforation is known to significantly compromise the outcome of endodontic treatment. One potential use of regenerative endodontic therapy might be the repair of root canal perforations. In addition to nutrients and systemic in situ interactions, the 3 main components believed to be essential for tissue regeneration are stem cells, scaffold, and growth factors. This study investigated the role of each component of the tissue engineering triad in the organization and differentiation of dental pulp stem cells (DPSCs) in a simulated furcal perforation site by using a mouse model. Collagen served as the scaffold, and dentin matrix protein 1 (DMP1) was the growth factor. Materials were placed in simulated perforation sites in dentin slices. Mineral trioxide aggregate was the control repair material. At 6 weeks, the animals were killed, and the perforation sites were evaluated by light microscopy and histologic staining. Organization of newly derived pulp tissue was seen in the group containing the triad of DPSCs, a collagen scaffold, and DMP1. The other 4 groups did not demonstrate any apparent tissue organization. Under the conditions of the present study, it might be concluded that the triad of DPSCs, a collagen scaffold, and DMP1 can induce an organized matrix formation similar to that of pulpal tissue, which might lead to hard tissue formation.

Outcome of One-visit and Two-visit Endodontic Treatment of Necrotic Teeth with Apical Periodontitis: A Randomized Controlled Trial with One-year Evaluation

The choice of one-visit versus two-visit root canal therapy for necrotic teeth with apical periodontitis is a source of current debate. The primary objective of this randomized controlled clinical trial was to compare radiographic evidence of periapical healing after root canal therapy completed in one visit or two visits with an interim calcium hydroxide/chlorhexidine paste dressing. Ninety-seven patients met the inclusion criteria and consented to participate in this study. Patients were randomly assigned to either the one-visit or two-visit group, and root canal therapy was performed with a standardized protocol. Patients in the two-visit group received an intracanal dressing of calcium hydroxide/chlorhexidine paste. Sixty-three patients, 33 in the one-visit group and 30 in the two-visit group, were evaluated at 12 months. The primary outcome measure was change in apical bone density by using the periapical index (PAI). Secondary outcome measures were proportion of teeth healed or improved in each group. Both groups exhibited equally favorable periapical healing at 12 months, with no statistically significant differences between groups.

Comparison of Endodontic Diagnosis and Treatment Planning Decisions Using Cone-beam Volumetric Tomography Versus Periapical Radiography

INTRODUCTION Accurate and confident treatment planning is an essential part of endodontic practice. Periapical radiographs have been used to aid in the diagnosis of pathology and to help establish an appropriate treatment strategy. Recently, a new imaging modality, cone-beam volumetric tomographic (CBVT) imaging, has been shown to be a useful tool in a number of endodontic applications. The aim of this study was to compare the relative value of preoperative periapical radiographs and CBVT scanning in the decision-making process in endodontic treatment planning. METHODS Thirty endodontic cases completed in a private endodontic practice were randomly selected to be included in this study. Each case was required to have a preoperative digital periapical radiograph and a CBVT scan. Three board-certified endodontists reviewed the 30 preoperative periapical radiographs. Two weeks later, the CBVT volumes were reviewed in random order by the same evaluators. The evaluators were asked to select a preliminary diagnosis and treatment plan based solely on their interpretation of the periapical and CBVT images. Diagnosis and treatment planning choices were then compared to determine if there was a change from the periapical radiograph to the CBVT scan. RESULTS A difference in treatment plan between the 2 imaging modalities was recorded in 19 of 30 cases (63.3%, P = .001), 17 of 30 cases (56.6%, P = .012), and 20 of 30 cases (66.7%, P = .008) for examiners 1, 2, and 3, respectively. CONCLUSIONS Under the conditions of this study, preoperative CBVT imaging provides additional information when compared with preoperative periapical radiographs, which may lead to treatment plan modifications in approximately 62% of the cases.

Biomimetic approach to perforation repair using dental pulp stem cells and dentin matrix protein 1.

INTRODUCTION Dentin regeneration could be an ideal treatment option to restore tissue function. This study was conducted to evaluate the ability of dental pulp stem cells (DPSCs) and dentin matrix protein 1 (DMP1) impregnated within a collagen scaffold to regenerate dentin. METHODS Simulated perforations were created in 18 dentin wafers made from freshly extracted human molars. Six groups were established. They were (1) empty wafers, (2) mineral trioxide aggregate, (3) collagen scaffold, (4) scaffold with DMP1, (5) scaffold with DPSCs, and (6) scaffold with DPSCs and DMP1. One sample was placed subcutaneously in each mouse with three mice in each group. After 12 weeks, the samples were subjected to radiographic, histological, and immunohistochemical evaluations. RESULTS DPSCs impregnated within a collagen scaffold differentiated into odontoblast-like cells forming a highly cellular, vascular, and mineralized matrix in the presence of DMP1. CONCLUSIONS A triad consisting of DPSCs, DMP1, and a collagen scaffold promotes dentin regeneration in a simulated perforation repair model.

Transient effects of low-energy CO2 laser irradiation on dentinal impedance: implications for treatment of hypersensitive teeth.

This study evaluated the effect of CO2 laser irradiation on dentinal impedance by passing known cyclic potentials across dentinal wafers mounted as a window in an electrolytic cell and measuring the resulting electrical impedance. Wafers were equilibrated in 0.1 M of KCl. The wafer specimens were irradiated with a CO2 laser (12 W, 0.1 ms, energy density 1.25 J/cm2). The time for impedance equilibration after irradiation was compared with equilibration after mounting. Mounted samples required 48 h to approach equilibrium in the electrolyte. After laser irradiation, impedance of previously equilibrated samples also required 48 h to equilibrate. This, along with exponential curve fitting, confirmed that laser treatment reintroduced a transient alteration in impedance. Equilibration time after irradiation and the mounting were similar. Dentin desociation apparently caused this transient impedance. Energy dispersive X-ray analysis confirmed the disappearance of K+Cl- after irradiation. Therefore, laser irradiation may cause dentinal desociation, yielding temporary clinical relief of dentinal hypersensitivity until rehydration occurs.

Biologic Markers for Odontogenic Periradicular Periodontitis

INTRODUCTION The diagnosis and assessment of apical periodontitis by traditional periapical radiographs can be challenging and might yield false-negative results. The aim of this study was to determine whether interleukin-1beta (IL-1beta) and dentin sialoprotein (DSP) in gingival crevicular fluid (GCF) can be used as biological markers for apical periodontitis. METHODS Forty healthy patients with teeth diagnosed with apical periodontitis of pulpal origin were included in the study. GCF samples were obtained from the diseased tooth and from a healthy contralateral control tooth. Total protein concentration in each sample was determined by using the Bio-Rad protein assay. Enzyme-linked immunosorbent assay was used to analyze the concentration of IL-1beta and DSP in the samples. RESULTS Protein content of the GCF was statistically significantly higher in the disease group compared with the control group. The levels of IL-1beta and DSP were not statistically different between disease and control groups. CONCLUSIONS Although this study was unable to demonstrate a significantly higher level of IL-1beta or DSP in the GCF of teeth with apical periodontitis, the observed presence of a significantly higher level of total protein in the GCF of diseased teeth suggests the possible role of total protein level as a marker for periapical disease.

Evaluation of canal cleanliness and smear layer removal after the use of the Quantec-E irrigation system and syringe: a comparative scanning electron microscope study.

OBJECTIVE The purpose of this study was to evaluate canal cleanliness and smear layer removal after use of the Quantec-E irrigation system and to compare the system with traditional irrigation. STUDY DESIGN Forty anterior teeth were randomly assigned to 4 groups. Group A consisted of 15 teeth that were instrumented with .12, .10, .08, .06 and .04 tapered rotaries while simultaneously irrigated via the Quantec-E irrigation pump with 12 mL of 5.25% NaOCl, followed by 6 mL EDTA 17% in crown-down fashion, with a final flush with 4 mL 5.25% NaOCl. Group B consisted of 15 teeth that were instrumented with the same instrument sequence, and irrigated with the same volumes via traditional needle and syringe. Group C consisted of 5 teeth that were sectioned and examined under a scanning electron microscope (SEM) without any instrumentation and served as a negative control. Group D consisted of 5 teeth that were instrumented dry, without any irrigation, and served as a positive control. All teeth were sectioned buccolingually and examined with SEM at 700x magnification in the apical, middle, and coronal portions of the canals. Analysis of SEM images was performed by 5 independent examiners using a 4-point scoring system. RESULTS Irrigation with the Quantec-E irrigation pump resulted in cleaner canal walls, less debris, and more complete removal of the smear layer within the coronal one third, when compared with syringe irrigation. However, no difference was observed in the middle and apical one thirds of the root canal. CONCLUSION There was no significant difference between the 2 irrigation systems.

Different Representations of Vertical Root Fractures Detected by Cone-Beam Volumetric Tomography: A Case Series Report

INTRODUCTION Vertical root fractures (VRFs) pose a clinical dilemma and a challenge to clinicians. Definitive diagnosis is often complicated by the lack of consistent signs and symptoms and the low sensitivity of conventional radiographs in the detection of VRFs. New radiographic imaging systems have recently become available for use in dentistry. Among these new imaging technologies is cone-beam volumetric tomography (CBVT). CBVT technology allows the precise visualization and evaluation of teeth with VRFs. The use of CBVT has great potential as a diagnostic tool to assist in the detection of VRFs. METHODS Seven cases are presented to demonstrate the use of CBVT in detection of VRFs in endodontically treated teeth. RESULTS Five specific findings on CBVT exam were consistent with confirmed VRFs. CONCLUSIONS As demonstrated in this case series, CBVT can provide valuable additional diagnostic information in the detection of VRFs and may help prevent unnecessary treatment.

Utilization of cone beam computed tomography in endodontic diagnosis

Endodontic diagnosis is dependent upon evaluation of the patient’s chief complaint, medical and dental history, and clinical and radiographic examination. A clinical examination must be performed before considering any radiographic examination. Imaging is an essential part of endodontic practice, from diagnosis and treatment planning to outcome assessment. Intraoral radiographs have inherent limitations due to the compression of three-dimensional (3D) structures in a two-dimensional (2D) image. Superimposition of anatomic structures and image noise results in distortion of the area of interest. The use of cone beam computed tomography (CBCT) could overcome these issues by visualizing the dentition and the relationship of anatomic structures in three dimensions. CBCT units reconstruct the projection data to provide interrelational images in three orthogonal planes (axial, sagittal, and coronal). For most endodontic applications, limited or focused field of view (FOV) CBCT is preferred over large volume CBCT. This chapter will review the utilization of CBCT in endodontic diagnosis and management of periapical pathosis, diagnosis of pain, cracked teeth and vertical root fractures, internal and external resorptive defects, and traumatic injuries.

The Impact of Cone Beam Computed Tomography in Nonsurgical and Surgical Treatment Planning

Development of an appropriate treatment plan follows diagnosis and could be considered the foundation of a successful outcome. Until the recent introduction of cone beam computed tomography (CBCT) for dental uses, two-dimensional radiographic imaging has been the standard for dental treatment planning. In endodontics, subjective history, clinical findings, and diagnostic imaging are all essential components of the preoperative diagnosis and treatment plan (Reit and Petersson Diagnosis of pulpal and periradicular disease. In: Bergenholtz G, Horsted-Bindslev P, Reit C, eds. Textbook of Endodontology. 2nd ed. Chichester/West Sussex: Wiley-Blackwell; 2010. p. 235–53). Conventional two-dimensional radiographs provide a cost-effective, high-resolution image, which continues to be the most popular method of imaging today. However, the diagnostic potential of periapical radiographs is limited. Information may be difficult to interpret, especially when the anatomy and background pattern is complex (Kundel and Revesz, Am J Roentgenol 126:1233–1238; 1976). Recently, CBCT has been demonstrated to be a useful tool in a number of endodontic applications. The aim of this chapter is to compare the relative value of preoperative periapical radiographs and CBCT in the decision-making process in nonsurgical and surgical endodontic treatment planning.