Sealing Ability of Dyract, Geristore, IRM, and Super-EBA as Root-End Filling Materials
Greer, West, Liewehr, and Pashley
Presence of Interleukin-4-Producing Cells for Human Bone Regeneration after Application of Guided Tissue Regeneration Membranes
Kabashima and Nagata
In Vitro Apical Leakage of System B Compared with Other Filling Techniques
Pommel and Camps
In Vitro Assessment of the Antimicrobial Action and the Mechanical Ability of Chlorhexidine Gel as an Endodontic Irrigant
Randi Ferraz, Figueiredo de Almeida Gomes, Zaia, Teixeira, and José de Souza-Filho
Microleakage of Root-End Filling Materials
Fogel and Peikoff
p53 Protein Expression in Odontogenic Cysts
Piattelli, Fioroni, Santinelli, and Rubini
Matrix Metalloproteinase-2 in Dentin Matrix Mineralization
Satoyoshi, Kawata, Koizumi, Inoue, Itohara, Teranaka, and Mikuni-Takagaki
Feline Immunodeficiency Virus Model to Study Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome Conditions
Levine, Gutmann, Witherspoon, Nunn, and Wiggs
Sealing Ability of Dyract, Geristore, IRM, and Super-EBA as Root-End Filling Materials
Bill D. Greer, DDS, Lesley A. West, DDS, MS, Fredrick R. Liewehr, DDS, MS, and David H. Pashley, DMD, PhD
The purpose of this study was to evaluate the apical sealing ability of two compomers (Dyract and Geristore), IRM, and Super-EBA. Forty single canal roots from human teeth were instrumented until a size 40 file extended 1 mm beyond the apex. One millimeter of root apex was removed and a preparation 3-mm deep was prepared. Roots were divided into 4 groups of 10 roots each and filled with IRM, Super-EBA, Dyract, or Geristore. Canals were not obturated to ensure that any leakage was due to the apical filling material alone. Each root was then affixed to a fluid filtration device and subjected to a pressure of 14 cm of H2O, which has been determined to be the normal pulpal tissue pressure. The integrity of the seal was evaluated for 5 min at 1, 7, 30, and 180 days. Data were analyzed at each time point using one-way analysis of variance on ranks. The results of this study suggest that the new compomers Dyract and Geristore are equal or superior to IRM and equivalent to Super-EBA in their ability to reduce apical leakage when used as retrofilling materials.
Presence of Interleukin-4-Producing Cells for Human Bone Regeneration after Application of Guided Tissue Regeneration Membranes
Hiroaki Kabashima, DDS, PhD, and Kengo Nagata, DDS, PhD
To study the process of bone regeneration we examined three samples of periapical regenerative tissue obtained form two patients under a guided tissue regeneration treatment in endodontic surgery by the immunohistochemical and enzyme histochemical methods. The regenerative tissue consisted of a large number of fibroblast-like cells and a small number of mononuclear cells. Fibroblast-like cells stained positively for alkaline phosphatase and osteopontin, whereas mononuclear cells stained positively for CD4. Interleukin-4-producing cells could not be detected in adjacent sections. However, interferon-γ-producing cells could be detected. These findings suggest that interleukin-4-producing cells may be one of the elements associated with success in the human bone regeneration process in vivo.
In Vitro Apical Leakage of System B Compared with Other Filling Techniques
Ludovic Pommel, DCD, and Jean Camps, DCD, PhD
A fluid filtration system was used to compare the apical microleakage of roots filled with the system B (Analytic Technology), single-cone technique, lateral condensation, vertical condensation, and Thermafil (Caulk-Dentsply). After preparation of the canal system with a Profile (Caulk-Dentsply) five groups of 10 single-rooted teeth were randomly filled according to 1 of the 5 techniques. Phosphate-buffered saline was forced under a 15 cm H2O pressure, through the apex, toward the coronal part of the root. The filtration rate in L s-1 Kpa-1 was recorded 24 h after filling and after 1-month storage in phosphate-buffered saline. The 24 h results showed that the single cone technique provided the highest leakage (p = 0.001). At 1-month system B, Thermafil and vertical condensation had less leakage than the two other techniques (p = 0.001): lateral condensation produced moderate apical leakage, whereas the single cone technique showed the highest leakage. Regardless of the technique the apical leakage increased after 1- month storage (p = 0.001 or p = 0.0001 depending on the technique).
In Vitro Assessment of the Antimicrobial Action and the Mechanical Ability of Chlorhexidine Gel as an Endodontic Irrigant
Caio Cezar Randi Ferraz, DDS, MSc, PhD, Brenda Paula Figueiredo de Almeida Gomes, DDS, MSc, PhD, Alexandre Augusto Zaia, DDS, MSc, PhD, Fabrício Batista Teixeira, DDS, MSc, PhD, and Francisco José de Souza-Filho, DDS, MSc, PhD
The objective of this study was to assess the chlorhexidine gluconate gel as an endodontic irrigant. First the ability of chlorhexidine gel to disinfect root canals contaminated in vitro with Enterococcus faecalis was investigated. A scanning electron microscope was also used to evaluate its cleansing ability compared with endodontic irrigants commonly used, such as sodium hypochlorite and chlorhexidine gluconate liquid. The results indicated that the chlorhexidine gel produced a cleaner root canal surface and had an antimicrobial ability comparable with that obtained with the other solutions tested. It was concluded that chlorhexidine gluconate in gel form has potential for use as an endodontic irrigant.
Microleakage of Root-End Filling Materials
Howard M. Fogel, DMD, MS, and Marshall D. Peikoff, DMD, MSc(D)
The purpose of this study was to evaluate the microleakage of various root-end filling materials using a fluid filtration system. Sixty extracted human single-rooted teeth were used. The crowns were removed, the canals prepared, and root-end fillings placed. The samples were divided into two control and five experimental groups. The root-end filling materials tested were: amalgam Intermediate Restorative Material (IRM), a dentin-bonded resin, Super-EBA, dentin-bonded resin, and mineral trioxide aggregate. The results showed that amalgam root-end fillings demonstrated significantly more microleakage than Super-EBA, dentin-bonded resin, or mineral trioxide aggregate. There was no significant difference between amalgam and IRM. However IRM was also not significantly different from the other three groups. There were not significant differences between the other three groups.
p53 Protein Expression in Odontogenic Cysts
Adriano Piattelli, MD, DDS, Massimiliano Fioroni, DDS, Alfredo Santinelli, MD, and Corrado Rubini, MD
p53 protein seems to be related to the suppressions of cell proliferation. p53-positive tissue seem to have a higher proliferation activity than p53-negative ones. Odontogenic keratocyst (OKC) has a different behavior from other types of cysts because it is more aggressive, with a tendency to recurrence. Twenty-two dentigerous cysts, 24 radicular cysts, and 20 OKCs were used in the present study. Two dentigerous cysts (9.1%), 2 radicular cysts (8.3%), and 9 OKCs (45%) expressed the p53 protein. The differences between the three groups were statistically significant (p = 0.003). In 10 cases of OKCs epithelial dysplasia was found. One of the 10 OCKs without dysplasia and 8 of the 10 OKCs with dysplasia were p53 positive: the difference between the two groups was statistically significant (p = 0.007). The overexpression of p53 protein was not on the other hand correlated with the occurrence of multiple, bilateral, land recurrent OCKs. Moreover the distribution of p53-positive cells was parabasal in contrast with other types of cysts. These qualitative and quantitative differences in proliferation activity in OKCs seem to pint to an alteration in cell cycle control.
Matrix Metalloproteinase-2 in Dentin Matrix Mineralization
Masanori Satoyoshi, DDS, PhD, Akira Kawata, DDS, PhD, Tadahiko Koizumi, DDS, PhD, Keiichi Inoue, MS, Shigeyoshi Itohara, DVM, PhD, Toshio Teranaka, DDS, PhD, and Yuko Mikuni-Takagaki, PhD
In the serum-free culture medium of bovine odontoblasts we detected active gelatinolytic metalloproteinases, matrix metalloproteinase (MMP)-2, and MMP-9 (gelatinases A and B). The activity of MMP-2, in particular, appeared suddenly around day 21 in the culture, coinciding with the development of odontoblastic cell processes and the loss of alkaline phosphatase. Reverse transcriptasepolymerase chain reaction analysis of these odontoblasts demonstrated that messages of MMP-2 but not MMP-9 increased significantly between day 15 and day 21. The in vitro observation indicates that medium conditioned by these odontoblasts and containing significant amounts of MMP-2 degrades not only the collagenous substrates but also purified dentin phosphophoryn as well. We have also observed that dephosphorylated dentin phosphoprotein becomes a better substrate for casein kinase II after limited proteolysis with MMP-2. These results support our working hypothesis that MMP-2-mediated proteolytic processing is an important step in accelerating the process of dentin matrix maturation, which includes phosphorylation and subsequent mineralization. As has been suggested previously, extra-cellular phosphorylation of matrix proteins is an important step in biomineralization both in bone and in dentin (Mikuni-Takagaki et al., J Bone Miner Res 1995; 10:231-42; Zhu et al., Biochem J 1997; 323:637-43). Our present histochemical analysis in MMP-2 knockout mice confirms the concept with the delayed formation of mineralized tissues, dentin, and bone.
Feline Immunodeficiency Virus Model to Study Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome Conditions
Débora F. Levine, DDS, MS, James L. Gutmann, DDS, David E. Witherspoon, BDS, MS, Martha E. Nunn, DDS, PhD, and Robert B. Wiggs, BS, DVM
This study was designed to induce rapid progression of the feline immunodeficiency virus (V) infection in cats. Predictably inducing the FIV disease state in the cat would yield an excellent tool to study endodontic disease processes under immunosupressed conditions. Eight cats were immunosupressed with steroids before infection with FIV. Another eight cats, age- and sex-matched littermates, served as uninoculated seronegative controls. Complete blood counts were taken for 10 mo in the FIV group and 10 wk in the control group, including lymphocytes subsets. ELISAs were used to detect FIV infection. Statistical analysis was performed with generalized estimating equation models. All cats were positive at one point in time. The FIV group had significantly lower peripheral blood CD4+ counts compared with the control group. Therefore the FIV model presented gives the desired outcome and simulates what occurs in human immunodeficiency virus infection.