[Revascularization? Only as the last resort!].

Revascularization has been suggested for treatment of necrotic immature permanent teeth. The desirable outcome of the treatment is continuous growth of the root, maturation of the dentin walls underneath the cervical seal and apical closure. Despite of increasing numbers of case reports, a uniform treatment protocol has not been set. This procedure has many shortcomings of which tooth discoloration is the most prevalent and easy to observe. The severe discoloration is attributed to the use of Mincocycline in the antibiotic dressing, or to the use of MTA for the seal. The maturation of the root is not predictable and does not always occur. The outcome should be evaluated radiographically and clinically. Sensibility testing may not be possible due to the large MTA plug in the root canal. It is recommended only when alternative procedures such as apexificaiton, pulpotomy or pulp capping are impossible. The patient and his parents should be aware of the potential discoloration and must be committed to routine follow ups. Currently, this procedure should be limited to incisor or premolar teeth in which the crown is longer than the root, or the canal's width is larger than that of the dentinal wall.

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.

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.

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.

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.

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.

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.

Endodontic retreatment of unusually long maxillary central incisors.

Anatomical and morphological variations in teeth may affect the success and prognosis of endodontic therapy. The reported data regarding such variations in the maxillary central incisors are limited. This article presents a case of endodontic retreatment in unusually long maxillary central incisors.

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.

Is herpes simplex virus associated with pulp/periapical inflammation?

OBJECTIVES: This study focuses on the detection of herpes simplex virus (HSV) DNA in dental pulp and inflamed periapical tissue. STUDY DESIGN: Dental pulp tissue (vital and necrotic) and periapical tissue samples were collected under strictly sterile conditions and examined for the presence of HSV DNA. Saliva samples were also examined for the presence of the viral DNA. The polymerase chain reaction assay was used to detect viral DNA. Blood samples were collected, and the enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies against HSV was carried out. RESULTS: According to the ELISA test, 19 of the 23 blood samples were IgG-positive and IgM-negative to HSV, whereas 4 were IgG-negative and IgM-negative. HSV DNA was not detected in the tissue and the saliva samples tested. CONCLUSION: HSV is not present and therefore is probably not involved in the pathology of tooth neural tissue.

Efficacy of three cavity liners in eliminating bacteria from infected dentinal tubules.

Three lining materials, Life, Ketac-Bond, and IRM, were investigated for their antibacterial effects within dentinal tubules. Sterile saline served as control. Sixty standardized bovine root specimens were infected with Enterococcus faecalis following smear layer removal. The materials were mixed according to manufacturer's directions and inserted in the canal lumina; additional IRM specimens received a softer than normal mix. Specimens were incubated for 24 hours or 7 days, after which dentinal samples were taken from within the lumina and the numbers of bacteria present were assessed. All the materials had a significant antibacterial effect after 7 days. Life demonstrated a more marked effect at 7 days than at 24 hours. The strongest antibacterial effect at 24 hours was shown by a "soft" mix of IRM. Ketac-Bond demonstrated an increase in antibacterial activity during the experimental period.

The outcome of teeth with periapical periodontitis treated with nonsurgical endodontic treatment: a computerized morphometric study.

OBJECTIVES: This study investigated the prognosis for successful endodontic treatment and the correlation between the size of the periapical lesion, the quality of the root canal treatment, and the type of coronal restoration. METHOD AND MATERIALS: Periapical radiographs of 319 teeth with periapical periodontitis were studied. The area of each lesion was measured before treatment and 1 to 12 years after completion of the endodontic treatment. The measurements were performed using computerized morphometry. RESULTS: In 65.2% of the teeth, the size of the lesion decreased, while in 34.8% of teeth, there was an increase. Lesions larger than 10 mm2 had a greater tendency for healing. CONCLUSION: No significant correlation was found between the quality of root canal treatment, the type of the coronal restoration, and the success rate of the endodontic treatment.

Delayed treatment of a mid-root fracture.

A case of delayed treatment of a mid root fracture is presented. A radiolucent lesion at the fracture line was treated with calcium hydroxide in the coronal fragment for nine months. Clinically, the tooth became firm and the radiographic results showed healing of the lateral lesion and hard tissue filling in the space at the fracture line.

Efficacy of Ledermix paste in eliminating Staphylococcus aureus from infected dentinal tubules in vitro.

The efficacy of Ledermix paste in disinfection of dentinal tubules was studied in a model developed by Haapasalo and Orstavik with some modifications. Ledermix and 3% Tetracycline in a hydrous base were effective in reducing the amount of Staphylococcus aureus in dentinal tubules after 7 days of incubation and also after recontamination. They were not effective after 24 h.

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.

Response of the dental pulp to capping with a composite resin-bonded ceramic and dental adhesive in rat molars.

An inflammatory response occurs in the pulp tissue following the application of dental materials due to their chemical properties and/or a secondary bacterial irritation. Recently, a new line of composite resin products with reported improved esthetic qualities was designed to allow an intimate adherence with the dentin. This intense bonding could prevent bacterial penetration and marginal discoloration of these restorations. In addition, this method allows prevention of excessive removal of hard tissue. The present study examines pulpal reaction to capping with P-10 composite resin (Dental Products, USA) in rats. Histological examination did not reveal any inflammatory reaction in the nonexposed pulps. Direct pulp capping with P-10 induced formation of reparative dentin bridges.