Evaluation of cetylpyridinium chloride for infection control in storage solution.

Storage solution is used in in vitro experimental studies to prevent dehydration of teeth collected immediately after extraction and to prevent bacterial and fungal growth in the storage media. The chemical nature of the storing agent may affect the tooth structure and material properties at the tested interface. The aim of this study was to evaluate the use of 0.1% cetylpyridinium chloride (CPC) as a new storage solution and to assess the possible effect of 0.1% thymol on microleakage and bond strength. Forty extracted human teeth were collected from 10 different dental clinics. Immediately after extraction, the teeth were randomly divided and immersed in four different storage solutions. Two test solutions of 0.1% CPC (group C) and 0.1% thymol (group T) were compared with phosphate-buffered saline (Group S - positive control) and to 3% H2O2 (group H - negative control). Bond strength test and dye penetration evaluation were then carried out. The findings suggest that the use of 0.1% CPC as storage solution does not affect bond strength to enamel. However, it may increase dye penetration at the cervical margin. The effect of 0.1% thymol on shear bond strength and dye penetration is similar to the effect of phosphate-buffered saline.

Effect of sodium hypochlorite and EDTA on mercury released from amalgam.

OBJECTIVES: The effect of sodium hypochlorite (NaOCl) and EDTA on mercury released from dental amalgam was assessed in vitro. STUDY DESIGN: Fifty-six samples of dental amalgam of similar size were prepared and exposed to a 10-mL solution of either 1% NaOCl, 3% NaOCl, 10% EDTA in 1% NaOCl, or 10% EDTA in 3% NaOCl for periods of 20, 40, and 60 minutes. Mercury concentrations in the solutions were measured by using a cold-vapor atomic absorption Mercury Analyzer System, and the differences between the groups were statistically analyzed. RESULTS: All amalgam samples exposed to 1% NaOCl and 3% NaOCl-either alone or in combination with EDTA-released mercury into the solutions. Mercury release was significantly higher in the test groups than in the EDTA, distilled water, or phosphate buffer controls (P <.001). Increase in the mean concentration levels of mercury in solution was time-dependent and directly related to NaOCl concentration. The addition of EDTA caused a reduction in mercury levels detected in solution, which was more significant in amalgam samples exposed to 1% NaOCl combined with EDTA (P <.001). CONCLUSIONS: NaOCl solutions commonly used for root canal cleaning and shaping cause mercury release from dental amalgam and may alter its chemo-physical properties as a sealant for root perforations.

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.

Stafne's bone cavity in the anterior mandible: a possible diagnostic challenge.

Stafne was the first to report the presence of "bone cavities" in the angle of 35 mandibles. Such cavities generally appear in the area between the mandibular first molar and the mandibular angle, and are not considered rare. One of their primary radiological diagnostic features is the characteristic location below the mandibular canal. Stafne's bone cavity is relatively rare in the anterior mandible. The mandibular canal is not present in the anterior mandible. As a result, diagnosis in the anterior mandible may be missed. Needless treatment modalities such as endodontic treatment, bone trephining, and bone exploration may be conducted. The purpose of the present report is to describe a new case of Stafne's bone cavity in the anterior mandible and discuss the differential diagnosis process. The dental computerized tomography scan is suggested as the most suitable noninvasive diagnostic and follow-up modality for this bony configuration in the anterior mandible.

Mercury release from dental amalgam after treatment with 10% carbamide peroxide in vitro.

OBJECTIVES: The effect of 10% carbamide peroxide on mercury release from dental amalgams was assessed in vitro by using a cold-vapor atomic absorption Mercury Analyzer System. STUDY DESIGN: Samples of 4 commercial brands of dental amalgam, Megaloy (Dentsply/Caulk, Milford, Del), Mega+ (CFPM, Aulnaye, France), Nongama 2 (Silmet, Or Yehuda, Israel), and Valiant Ph.D. (Dentsply/Caulk, Milford, Del), were treated for 48 hours with 10% carbamide peroxide and compared with samples treated with phosphate buffer. RESULTS: Amalgam specimens exposed for 48 hours to 10% carbamide peroxide showed significantly higher concentrations of mercury in solution as compared with specimens treated with phosphate buffer (P <.001). Megaloy and Valiant Ph.D. yielded significantly higher mercury concentrations in solution than Mega+ and Nongama 2 (P <.001). Mega+ yielded significantly higher mercury concentrations in solution than Nongama 2 (P <.05). No significant differences were found in mercury concentrations in solution between Megaloy and Valiant Ph.D. CONCLUSIONS: Treatment with 10% carbamide peroxide bleaching agents caused an increase in mercury release from amalgam restorations, possibly increasing exposure of patients to its adverse effects. Amalgam brands differed in the amounts of mercury release after bleaching with carbamide peroxide.

A multidisciplinary approach to the treatment of an intruded maxillary permanent incisor complicated by the presence of two mesiodentes.

Treatment of a traumatically intruded maxillary incisor with an immature apex remains controversial. Treatment options include observation, surgical repositioning, or orthodontic forced eruption. Likewise, the ideal timing of surgical removal of a mesiodens is highly controversial: immediate versus delayed intervention. The complications associated with untreated supernumerary teeth include: overretention of primary teeth, delayed eruption of permanent incisors, rotations, impaction, diastema, pulp necrosis and root resorption. Less common sequelae include enlarged follicular sacs, cystic degeneration and nasal eruption. This paper describes another risk factor associated with delayed removal of a mesiodens previously not mentioned in the dental literature, namely potential complications arising from a traumatic injury, in particular intrusion, of the maxillary permanent incisors.

Effect of gutta-percha solvents on surface microhardness of IRM fillings.

Eighty identical samples of IRM were prepared and embedded in acrylic resin. The samples were polished, rinsed, and divided into experimental groups and controls, 10 specimens each. Each experimental group was treated for 1 or 5 min with one of the following gutta-percha solvents: chloroform, xylene, or halothane. Sterile saline was used as a control. Treatment consisted of pipetting each solvent onto the external IRM surface. The specimens were then sealed in plastic assay tubes for the corresponding exposure periods. At each time period, surface microhardness of the samples was measured using a mini-load hardness tester with a 500 g load for 20 s. It was found that xylene and halothane caused significant reduction in surface microhardness of IRM after 5 min (p < 0.01). Chloroform caused significant reduction in surface microhardness of IRM after 1 min of treatment (p < 0.01). Chloroform caused total dissolution after 5 min of treatment. Saline caused only minor and nonsignificant changes in surface microhardness of IRM.

Protective effect of Copalite surface coating on mercury release from dental amalgam following treatment with carbamide peroxide.

The effect of Copalite coating on mercury release from dental amalgam following treatment with 10%, 20%, 30% and 40% carbamide peroxide was assessed in vitro, using a cold-vapour atomic absorption Mercury Analyzer System. Eighty samples of dental amalgam were automatically mixed in a dental amalgamator and condensed into silicon embedding molds. Forty amalgam samples were coated with three uniform layers of Copalite intermediary varnish and the other 40 samples were left uncoated. The coated and non-coated amalgam samples were exposed for 24 h to 10%, 20%, 30% or 40% carbamide peroxide preparations and compared with samples exposed to phosphate buffer. In the non-coated samples a significant increase of mercury concentration in solution was found following exposure to all carbamide peroxide preparations tested. Mercury concentration was directly related to carbamide peroxide concentration. In the Copalite-coated samples, significantly lower concentrations of mercury in solution were found as compared to the non-coated samples (P < 0.01). In conclusion, exposure of amalgam restorations to 10%-40% carbamide peroxide-based bleaching agents increased the mercury release. Pre-coating of the external amalgam surfaces with Copalite significantly reduced the release of mercury.

Effect of salivary biofilm on the adherence of oral bacteria to bleached and non-bleached restorative material.

OBJECTIVE: The objective of this work was to examine the effect of in vitro salivary biofilm on the adherence of oral bacteria to bleached and non-bleached restorative material (Charisma). METHODS: Charisma samples, prepared in silicon models, were treated with either 10% carbamide peroxide (CP) or 10% hydrogen peroxide (HP). After incubation with the bleaching agent for a period of one, two or three days, the samples were coated with freshly collected human saliva. The adsorption pattern of the saliva to the restorative material was determined using gel electrophoresis coupled with computerized densitometry techniques. The amount of salivary proteins adsorbed onto the treated surfaces was measured using the Bradford method. Sucrose-dependent bacterial adhesion to the salivary-coated Charisma was tested using radio-labeled Streptococcus mutans, Streptococcus sobrinus and Actinomyces viscosus. Adhesion of each bacterium to surfaces pretreated with the bleaching agents was compared with saliva coated bleached surfaces. RESULTS: The profile of salivary proteins adsorption followed a similar pattern in Charisma samples pretreated with either CP or HP or untreated samples. However, the total amount of salivary proteins adsorbed onto the samples decreased after bleaching with CP or HP. Salivary biofilm, coating the surface of the restorative material, significantly decreased sucrose-dependent adhesion of Streptococcus sobrinus and Streptococcus mutans to the bleached and non-bleached surfaces, compared to non-coated specimens (p < 0.05). Saliva had a minor effect on adhesion of Actinomyces viscosus. SIGNIFICANCE: Our study demonstrates the importance of salivary biofilm in controlling adhesion of oral bacteria to restorative material pretreated with bleaching agents or untreated.

Effect of chloroform, xylene, and halothane on enamel and dentin microhardness of human teeth.

OBJECTIVE: The purpose of this study was to assess in vitro the effect of commonly used gutta-percha solvents on the microhardness of human enamel and dentin. STUDY DESIGN: Crowns of human teeth were cut and treated with chloroform, xylene, and halothane. Treatment consisted of exposing the specimens for 5 or 15 minutes to the test solvents. Acid-treated and saline-treated specimens served as controls. After each treatment period, the specimens were rinsed, dried, and prepared for Vicker's microhardness analysis. Vicker's microhardness values for each specimen were recorded before and after treatment, and the differences were statistically compared. RESULTS: A statistically significant decrease in enamel and dentin microhardness was found in most solvent-treated groups; the amount of the decrease was directly related to the exposure time. CONCLUSIONS: Chloroform, xylene, and halothane may cause a significant softening effect on both enamel and dentin. This softening is already apparent after 5 minutes of treatment.

Bacterial adherence to bleached surfaces of composite resin in vitro.

OBJECTIVE: The effect of bleaching agents on bacterial adherence to polished surfaces of composite resin restorations was assessed in vitro. STUDY DESIGN: Samples of light-curing composite resins were treated with either 10% carbamide peroxide or 10% hydrogen peroxide for 1, 3, or 7 days. Bacterial adherence of Streptococcus mutans, Streptococcus sobrinus, and Actinomyces viscosus to the treated resin samples was analyzed and compared with adherence to nonbleached controls. RESULTS: A 10% solution of carbamide peroxide caused a significant increase in surface adherence of Streptococcus mutans and Streptococcus sobrinus after 3 days (P < .01). A 10% solution of hydrogen peroxide caused a significant increase in surface adherence of Streptococcus mutans and Streptococcus sobrinus after 3 and 7 days (P < .01). A decrease in adherence of Actinomyces viscosus was found after treatment with 10% hydrogen peroxide for 7 days (P < .05). CONCLUSIONS: It appears that bleaching agents may affect adherence of certain cariogenic microorganisms to the outer surfaces of composite resin restorations.

Internal coronal resorption of a permanent molar: a conservative approach for treatment.

A case of internal coronal resorption in a maxillary first permanent molar of a young adult is described. Conservative treatment was done, which included endodontic therapy followed by coronal restoration with bonded composites. The importance of early diagnosis and treatment of the resorptive defect is stressed.

Endodontic therapy for a fused mandibular molar.

Variations in tooth morphology present a clinical challenge when endodontic treatment is required. A case of conservative endodontic therapy for a fused mandibular second and third molar is presented.

Changes in surface levels of mercury, silver, tin, and copper of dental amalgam treated with carbamide peroxide and hydrogen peroxide in vitro.

OBJECTIVES: The effect of 10% carbamide peroxide or 10% hydrogen peroxide on the surface levels of mercury, silver, tin, and copper of amalgam fillings was tested in vitro with scanning electron microscopy and energy dispersive spectrometric microanalysis. STUDY DESIGN: Samples of amalgam were treated for 14 and 28 days with either 10% carbamide peroxide or 10% hydrogen peroxide solutions and compared with phosphate buffer controls. RESULTS: A significant increase in mercury levels occurred after treatment with carbamide peroxide for 14 days (p < 0.01) and 28 days (p < 0.001) and after treatment with hydrogen peroxide for 28 days (p < 0.001). A significant increase in silver levels occurred after treatment with carbamide peroxide for 14 days (p < 0.05) and 28 days (p < 0.01) and subsequent to treatment with hydrogen peroxide for 14 days (p < 0.05) and 28 days (p < 0.001). A significant reduction in tin levels occurred after treatment with hydrogen peroxide for 14 days (p < 0.01) and 28 days (p < 0.001), and after treatment with carbamide peroxide for 28 days (p < 0.01). A significant reduction in copper levels was found after treatment with carbamide peroxide for 14 days (p < 0.05). CONCLUSIONS: It appears that prolonged treatment with bleaching agents may cause microstructural changes in amalgam surfaces, possibly increasing exposure of patients to toxic byproducts.

Effect of XeCl-308nm excimer laser on the mineral content of human dentin.

The effect of the XeCl-308nm excimer laser on the mineral content and surface morphology of cut dentin was examined in ten extracted human teeth. Each dentin specimen was lased for 4 s at a fluence of 1 J/cm2 and a frequency of 25 Hz. Non-lased area of the same specimen served as control. Scanning electron microscopy and energy dispersive spectrometry revealed a significant decrease in the phosphorus levels following laser treatment. A decrease in calcium levels also occurred but was not statistically significant. Nonsignificant changes in sulphur and potassium levels were also noted. Morphologically, the lased dentin showed an apparently melted surface with partial obstruction of the dentin tubules as well as cracks along the lased surface. Therefore, it appeared that laser treatment may alter the chemical structure as well as the surface morphology of the dentin.

Effect of gutta-percha solvents on calcium and phosphorus levels of cut human dentin.

Fresh intact human teeth were cut and treated with 3 commonly used gutta-percha solvents: chloroform, xylene, and Endosolv-E. Treatment consisted of embedding the specimens of each group for 15 or 30 min in the test solution. After each time interval, the specimens were rinsed, dried, and prepared for surface energy dispersive spectrometric analysis. The calcium and phosphorus levels in each specimen were recorded and the differences between the test groups were statistically analyzed. The changes in the calcium and phosphorus levels following treatment with the gutta-percha solvents were minimal and statistically nonsignificant.

Mental nerve paresthesia associated with a non-vital tooth.

Apical periodontitis is a common development associated with teeth with necrotic pulp. Although rare, some cases may present further complications, such as neuropathies in areas adjacent to the affected tooth. A case is described in which mental nerve paresthesia was associated with a non-vital mandibular premolar. Endodontic therapy resolved the paresthesia completely without further clinical complications.

Conservative treatment of dens evaginatus of anterior teeth.

Dens evaginatus is a developmental malformation characterized by the presence of an extra cusp. In the anterior dentition, dens evaginatus is more commonly found in the maxilla and on the palatal surface of the tooth. Treatment may include root canal therapy followed by either an aesthetic restoration or a full crown coverage. In cases of mesiodens, supernumerary teeth or crowded dentition, extraction is often indicated. Presented is a case of a conservative treatment modality of dens evaginatus in a mandibular central incisor.

Dens evaginatus of anterior teeth. Literature review and radiographic survey of 15,000 teeth.

Case reports published between 1970 and 1995 that describe the characteristics of dens evaginatus of anterior teeth were reviewed. In addition, a radiographic survey of 15,000 anterior teeth was conducted to determine the occurrence of this developmental malformation. In this survey, dens evaginatus was found in about 1% of the anterior dentition and was more frequent in the maxilla, particularly in the lateral incisor. This anomaly was less frequent in the mandible.

Surface morphology changes in human enamel, dentin and cementum following bleaching: a scanning electron microscopy study.

Extracted human premolars were cut, cleaned and divided into 6 experimental groups. Each group was treated with one of the following bleaching materials: 30% hydrogen peroxide, 10% carbamide peroxide, sodium perborate, Nu-Smile, Opalescence and DentlBright. Morphological changes in tooth surface occurred following treatment with most bleaching agents. Hydrogen peroxide and DentlBright were associated with surface changes in all dental tissues. Hydrogen peroxide, DentlBright, Nu-Smile and Opalescence were mainly associated with surface changes in the cementum, which exhibited more changes than the other tissues.