Ilana Heling

Histochemical analysis of dental hard tissues following bleaching.

The effect of commonly used bleaching materials on the dental hard tissues was tested in extracted human premolars. In each tooth, the apical two-thirds of the root was removed, and the remaining tooth stump was cut longitudinally into two equal segments. The segments were cleaned, dried, and divided into six experimental groups. Each group was treated with one of the following bleaching materials: 30% hydrogen peroxide (HP), 10% carbamide peroxide (CP), sodium perborate (SP), Nu-Smile (NS), Opalescence (Op), and DentlBright (DB). Treatment consisted of immersing the specimens in the respective test material followed by incubation at 37 degrees C for 7 days. The levels of calcium, phosphorus, sulfur, and potassium were measured in the enamel, dentin, and cementum. In the enamel, a significant reduction in the calcium/phosphorus (Ca/P) ratio was found following treatment with HP. In the dentin, a significant reduction in Ca/P ratio was found following treatment with HP,CP, DB, and Op. In the cementum, a significant reduction in the Ca/P ratio was found following treatment with HP, CP, NS, and Op. Changes in sulfur and potassium levels also occurred, but were usually not statistically significant. Significant reduction in sulfur levels occurred only in the cementum following treatment with CP and SP. Sulfur levels increased significantly following treatment with NS. Significant reduction in potassium levels occurred only in the dentin following treatment with CP. It is concluded that bleaching materials may adversely affect the dental hard tissues and should be used with caution.

The Antimicrobial Effect within Dentinal Tubules of Four Root Canal Sealers

The aim of this study was to investigate four root canal sealers--Pulp Canal Sealer EWT, Sealapex, AH26, and Ketac-Endo--for their antibacterial effects within dentinal tubules. Sterile saline served as a control. Sixty-six standardized bovine root specimens were infected with Enterococcus faecalis following smear layer removal. The materials were placed in the lumina, and six specimens from each group were stored for 24 h (48 h for AH26) and 7 days, after which dentin samples were taken from within the lumina using ISO 023 to 035 burs. Powder samples were incubated and the quantity of bacteria present assessed using spectrophotometry. All sealers showed antibacterial activity at 24 h, except Ketac-Endo. The activity of Pulp Canal Sealer EWT was similar at 24 h and 7 days. Sealapex had greater antibacterial effect at 7 days than it did at 24 h. The strongest effects were demonstrated by AH26.

Bactericidal and Cytotoxic Effects of Sodium Hypochlorite and Sodium Dichloroisocyanurate Solutions In Vitro

The antimicrobial and cytotoxic effects of sodium hypochlorite (NaOCl) and sodium dichloroisocyanurate (NaDCC) were evaluated and compared in vitro. The minimal inhibitory concentration and minimal bactericidal concentration of NaOCl and NaDCC were tested for Streptococcus sobrinus, Streptococcus salivarius, Enterococcus faecalis, and Streptococcus mutans. The cytotoxic effect was assessed by using human fibroblast tissue culture. Survival rate was assessed by a protein determination method. Results showed that the minimal inhibitory concentration and minimal bactericidal concentration values of NaOCl and NaDCC for the tested bacteria were in a similar range. NaDCC in concentrations higher than 0.02%, and NaOCl in concentrations higher than 0.01% were lethal to fibroblasts. In conclusion it seems that both agents were very effective in killing bacteria, and their cytotoxicity to fibroblasts in tissue culture was similar.

Effect of bleaching agents on dentin permeability to Streptococcus faecalis

Bacterial contamination of dentin may be a contributing factor in the development of bleaching-associated root resorption. In this study, the effect of commonly used bleaching agents on the permeability of dentin tubules to Streptococcus faecalis was evaluated. Sixty extracted bovine incisors were horizontally sectioned apically to the cementoenamel junction. In each tooth, a standard cavity was prepared, the pulp tissue extirpated, and remnants of soft tissue and smear layer were removed. Following rinsing and repeated autoclave sterilization, the teeth were divided into four groups, each treated with one of the following materials: 30% hydrogen peroxide, sodium perborate mixed with 30% hydrogen peroxide, sodium perborate mixed with distilled water, and distilled water alone that served as control. The bleaching agents were sealed in the teeth and incubated at 37 degrees C for 7, 14, and 21 days. At each time interval the bleaching agents were removed and the teeth incubated at 37 degrees C in brain heart infusion infected with S. faecalis. Histological sections were prepared, and the maximal bacterial penetration for each group was measured using a computerized morphometric system. Statistical analysis of the results revealed that teeth treated with either 30% hydrogen peroxide alone or in combination with sodium perborate were significantly more permeable to S. faecalis than those treated with sodium perborate mixed with water (p < 0.0001). Sodium perborate mixed with water did not cause an increase in dentin permeability to S. faecalis and was similar to the water control. In conclusion, it seems that bleaching agents containing hydrogen peroxide in high concentrations may increase bacterial penetration through dentinal tubules.

The effect of using an alternative irrigant between sodium hypochlorite and chlorhexidine to prevent the formation of para-chloroaniline within the root canal system.

AIM To determine if the formation of para-chloroaniline (PCA) can be avoided by using an alternative irrigant following sodium hypochlorite but before chlorhexidine. METHODOLOGY Fifty-five single-rooted teeth were decoronated, instrumented to size 40, .06 taper whilst being irrigated with 14% ethylene-diamine-tetra-acetic acid (EDTA) and 6% NaOCl. Samples were then randomly divided into three experimental and two control groups. Group 1 was irrigated with saline followed by 2% chlorhexidine gluconate (CHX). Group 2 was irrigated with 50% citric acid (CA) followed by 2% CHX. Group 3 was irrigated with 14% EDTA followed by 2% CHX. The chemical identity and quantification of the PCA in the formed precipitate was determined using gas chromatography/mass spectrometry (GC/MS). RESULTS All experimental groups contained PCA. The mean level of PCA for group 1 (sterile saline) was 229 ng mL(-1), group 2 (citric acid) 72 ng mL(-1) and group 3 (EDTA) 400 ng mL(-1), respectively. A significant difference was found between the saline and EDTA groups and the negative control (P < 0.05). Although no statistical significance was found between the negative control and citric acid group, PCA was still present in this experimental group. CONCLUSIONS Citric acid used as the intermittent irrigant had the least amount of PCA formation in the canal system. Until the threshold required to cause biological damage in humans is determined, the combination of NaOCl and CHX in root canal treatment should be avoided.

Cytotoxic chemotherapy-induced odontalgia: a differential diagnosis for dental pain.

INTRODUCTION Peripheral neurotoxicity and neuropathic pain are well-known complications of several anti-cancer chemotherapeutic agents. Such pain might cause an impairment of the patients quality of life and is a common limiting factor of anti-cancer chemotherapy. Neurotoxicity in orofacial structures has been previously described as diffuse jaw pain or numbness. Currently, localized pulpal pain is not listed as a possible complication of cytotoxic therapy. The aim of this report was to suggest cytotoxic-induced neurotoxicity as a differential diagnosis for toothache during anti-cancer therapy. METHODS We described the diagnostic process in a patient suffering from severe pulpal pain in apparently intact teeth during cytotoxic therapy. A non-Hodgkins lymphoma patient complained of 2 episodes of excruciating dental pain evoked by mouth breathing, which caused nocturnal awakenings. RESULTS Both episodes developed immediately after administrations of cyclophosphamide as part of an anti-cancer chemotherapy protocol. Clinical parameters and radiographic characteristics eliminated other possible dental and facial etiologies. Pulp extirpation (pulpectomy) resulted in immediate pain relief. In both episodes, cytologic evaluation of the extirpated pulp tissue failed to show inflammation or an infiltration of lymphoma cells. CONCLUSIONS This case presented a circumstantial relation between the clinical presentation of dental pain, with associated significant impairment of the patients quality of life, and the timing of administrations of high-dose cyclophosphamide. It suggests that chemotherapy-induced toxicity might manifest as pulpitis-like toothache, which might present a diagnostic challenge for the dental practitioner.

Endodontic procedures must never be performed without the rubber dam

The rubber dam is an absolute essential in all endodontic procedures. In documentation of that fact, we have presented the case of a 50-year-old man who swallowed an endodontic broach during endodontic treatment; the instrument passed through the gastrointestinal tract without difficulty.

In vitro antimicrobial effect of RC-Prep within dentinal tubules.

The antimicrobial effect of RC-Prep and its components--10% urea peroxide, 15% EDTA, and glycol--were evaluated individually, in vitro, within dentinal tubules. Standardized bovine incisor root specimens that had been infected with either Staphylococcus aureus or Streptococcus peltzer were incubated with each agent for 10 and 45 min. After exposure to the agent, dentin samples were collected from within the lumina using ISO 23 to 31 burs. Dentin powder samples were incubated with bacterial broth, and the amount of bacteria present was assessed by spectrophotometry. All agents tested were more effective in killing bacteria after incubation for 45 min than after 10 min.

Intraligamentary injection of slow-release methylprednisolone for the prevention of pain after endodontic treatment

The intraligamentary injection of a slow-release steroidal, the anti-inflammatory agent slow-release methylprednisolone (Depomedrol), was compared to a placebo and to an active placebo (Mepivacaine) in preventing postoperative pain after root canal treatment. The results clearly demonstrated that the tested drug significantly reduced the frequency and intensity of postoperative pain sequelae in the experimental set-up.

A persistent oronasal sinus tract of endodontic origin.

Extraoral sinus tracts of endodontic origin may be confused with a wide variety of diseases. Although they may be located in a variety of sites on the face and neck, once diagnosed the treatment is relatively simple and successful. Endodontic therapy is the treatment of choice in these cases; however, periapical surgery may occasionally be required. A case of persistent oronasal sinus is described in which healing occurred only after surgical removal of the involved lesion.