Is hard tissue formation in the dental pulp after the death of the primary odontoblasts a regenerative or a reparative process?

Objectives: Conceptually, two types of tertiary dentine may be produced in response to caries and environmental irritations: "reactionary dentine" that is secreted by existing primary odontoblasts and "reparative dentine", formed after the death of the odontoblasts by proliferation and differentiation of progenitor cells into odontoblast-like cells. Because histologic evidence for tubular dentine generated by newly differentiated odontoblast-like cells is lacking in human teeth, the present study examined pulpal cellular changes associated with caries/restorations, in the presence or absence of pulpal exposures.

Methods: Ninety-six extracted human teeth were histologically processed and serial sectioned for light microscopy: 65 contained untreated enamel/dentine caries; 20 were heavily restored and 11 had carious exposures managed by direct pulp-capping.

A prospective cohort study of endodontic treatments of 1,369 root canals: results after 5 years.

Objective: The purpose of this prospective study was: 1) to follow-up a large number of endodontic treatments performed by a single operator, periodically checked over a 5-year period; and 2) to correlate outcome to a number of clinical variables.

Study Design: This prospective study included all consecutive cases during the selected time period. All cases were followed regularly for a 5-year period.

Influence of a passive sonic irrigation system on the elimination of bacteria from root canal systems: a clinical study.

Introduction: The present investigation evaluated the ability of a new passive sonic irrigation (sonic group) system (EndoActivator) to eliminate cultivable bacteria from root canals in vivo and compared it with that of standard syringe irrigation (control group).

Methods: Data were obtained by using bacteriologic sampling of root canals treated by endodontic residents. Sampling results from 1 session of treatment were then compared with results obtained after intervisit calcium hydroxide disinfection and a second session of treatment.

Cytotoxicity evaluation of endosequence root repair material.

Objective: The purpose of this study was to evaluate the cytotoxicity of EndoSequence Root Repair Material (Brasseler USA, Savannah, GA) and compare it with gray and white MTA.

Study Design: Samples of 2 mg freshly mixed or set gray MTA (GMTA), white MTA (WMTA), EndoSequence Root Repair Material (ERRM), and AH26 were eluted with 300, 600, and 1,000 microL cell culture medium for 24 and 72 hours. L929 cells were seeded into 96-well plates at 3 x 10(4) cells/well and incubated with 100 microL elute from each elute group.

Wound healing of apical tissues after root canal therapy: a long-term clinical, radiographic, and histopathologic observation study.

Objective: The purpose of this study was to evaluate the pulp healing process and the dentin-cementum complex in 51 endodontically treated human teeth after long observation periods and to correlate histologic observations with conventional periapical radiographic findings.

Study Design: Specimens were obtained from the extraction of 77 treated teeth, which were deemed to be unrestorable, with no evidence of periapical bone lesion at the follow-up. After stringent evaluation of the radiographs, 51 cases that 3 independent evaluators assessed as having normal periapical conditions were selected.

Chronologic comparison of root dentin moisture in extracted human teeth stored in formalin, sodium azide, and distilled water.

This study quantified in vitro the root dentin moisture when 10% formalin (group A), 3% sodium azide (group B), and distilled water (group C) were used as teeth storage media. The root dentin moisture of 66 extracted human mandibular single-rooted teeth was measured at baseline (day 0) and at 1, 3, 7, and 14 days using a digital grain moisture meter. The baseline dentin moisture value was used as covariate in the generalized estimating equation (GEE) analysis.

Root dentin body moisture changes caused by ascorbic acid.

Objectives: To quantify in vitro the root dentin moisture (DM) when soaked in 10% ascorbic acid solution (Group A) and distilled water (Group B) for up to 14 days.

Methods: Forty-four extracted human mandibular single-rooted teeth were sectioned perpendicular to the long axis at the CEJ to access the root dentin. The samples were divided into Groups A and B.

Particle size and shape of calcium hydroxide.

The aim of this study was to examine the particle length, width, perimeter, and aspect ratio of calcium hydroxide powder using a flow particle image analyzer (FPIA). Five sample groups each with 10 mg of calcium hydroxide were mixed with 15 mL of alcohol and sonicated. Digital images of the particle samples were taken using the FPIA and analyzed with a one-way analysis of variance.

A rapid nondestructive method for root dentin moisture measurements: in vitro pilot study.

Dentin moisture content is important in adhesive bonding and structural strength research; however, there is no rapid method available to assess dentin moisture without sample destruction. This study examined the use of a digital grain moisture meter to measure root dentin moisture in vitro. Extracted mandibular single-rooted teeth were sectioned at the CEJ.

Stimulation of cytokines in osteoblasts cultured on enamel matrix derivative.

Objective: The purpose of this study was to evaluate the influence of enamel matrix derivative (EMD) on the release of transforming growth factor beta 1 (TGF-beta1), interleukin-6 (IL-6), insulin-like growth factor I (IGF-I), bone morphogenetic protein 2 (BMP-2), and osteoprotegerin (OPG) in human and mouse osteoblasts.

Study Design: Human MG-63 and mouse MC3T3-E1 cells were seeded onto 6-well culture plates at an initial density of 5,000/cm(2) and grown in Dulbecco's eagle medium (DMEM) with 10% fetal bovine serum for 24 h. Then cells were cultured either with 100 microg/mL EMD added to DMEM or with DMEM only.

Particle size and shape analysis of MTA finer fractions using Portland cement.

The aim of this study was to observe particle length, width, perimeter, and aspect ratio of mineral trioxide aggregate finer fractions using Portland cement. The High Power Field mode of the flow particle image analyzer was used for analysis. Images of particle samples were automatically collected by the analyzer along with analysis parameters.

Application of small interfering RNA for inhibition of lipopolysaccharide-induced osteoclast formation and cytokine stimulation.

RNA interference (RNAi) is a unique and powerful tool used for the study of gene function by suppressing its expression. Nuclear factor of activated T cells (NFATc1) is the most strongly induced transcription factor mediated by receptor activator for nuclear factor kappa B ligand stimulation and has shown to be a key regulator of osteoclastogenesis. To determine the application of small interfering RNA (siRNA) for inhibition of lipopolysaccharide (LPS)-induced cytokine stimulation and osteoclast formation, murine monocyte, RAW 264.

Comparative analysis of the particle size and shape of commercially available mineral trioxide aggregates and Portland cement: a study with a flow particle image analyzer.

The aim of this study is to characterize the particle size distribution and circularity of various Mineral Trioxide Aggregates (MTA) (ProRoot MTA/ MTA Angelus/Gray and White) and Portland cements with effective size ranges of 1.5-160 microm using a flow particle analyzer (Sysmex FPIA-3000, Kobe, Japan). Cumulative percentage of particles between 6 and 10 microm were, 65, 73, 48, 53, and 70 %, for Gray ProRoot MTA, White ProRoot MTA, Gray MTA Angelus, White MTA Angelus, and Portland cement, respectively.

Endodontic treatment outcome: effect of the permanent restoration.

Objective: To investigate the relationship between the presence of the coronal restoration and endodontic treatment success or failure.

Methods: This study comprised 200 endodontically treated teeth with 441 roots. Follow-up examination was conducted 4 +/- 0.

Emdogain-gel stimulates proliferation of odontoblasts and osteoblasts.

Objective: The purpose of this study was to determine whether a premixed form of enamel matrix derivative (EMD), Emdogain-gel, has the same property as the original formula of EMD in stimulating the proliferation of osteoblasts and odontoblasts.

Study Design: Osteoblast cell line (MC3T3) and odontoblast cell line (MDPC) were cultured in the 6-well culture plates and treated in 4 different groups: (1) culture medium control, (2) 100 microg/mL Emdogain-gel directly added to the culture medium, (3) culture medium with a culture plate insert, and (4) 100 microg/mL Emdogain-gel added onto a culture plate insert. The culture plate insert prevented direct contact between Emdogain-gel and the cells.

Three-dimensional visualization of a mandibular first molar with three distal roots using computer-aided rapid prototyping.

Nonsurgical endodontic therapy of a right mandibular first molar with 3 distal roots was successfully performed with the aid of magnification. 3D data (DICOM format) of the tooth were obtained from a CT HighSpeed Advantage and a Denta Scan program produced by GE Medical Systems. The CT protocol used for this procedure involved a slit thickness of 1 mm.

Effectiveness of a calcium hydroxide and chlorhexidine digluconate mixture as disinfectant during retreatment of failed endodontic cases.

Objective: The purpose of this in vivo investigation is to compare the effect of a slurry of Ca(OH)2 mixed in aqueous 2% chlorhexidine (CHX) versus aqueous Ca(OH)2 slurry alone on the disinfection of the pulp space of failed root-filled teeth during endodontic retreatment.

Study Design: Forty single-rooted previously root-filled teeth with associated periradicular lesions were included. The teeth were nonsurgically retreated and medicated over 3 treatment visits with 7-10-day intervals with either Ca(OH)2 in water or Ca(OH)2 in 2% aqueous CHX.