Zvi Fuss

An evaluation of endodontically treated vertically fractured teeth

For this survey, 92 vertically fractured endodontically treated teeth were evaluated clinically and radiographically before and after extraction. The maxillary second premolars (27.2%) and mesial roots of the mandibular molars (24%) were the most fractured teeth. In 67.4% of the teeth, a solitary buccal pocket was present; in 34.8%, a fistula frequently appeared closer to the gingival margin than to the apical area. A lateral radiolucency or a combination of lateral and periapical radiolucency was found in more than half of the cases. The general practitioners correctly diagnosed vertical root fracture in only one-third of the 92 fractured teeth in this survey.

Assessment of reliability of electrical and thermal pulp testing agents

The reliability of several pulp testing agents was compared in intact human premolar teeth. The electric pulp tester, CO 2 snow and dichlorodifluoromethane were found to be more dependable than ethyl chloride and ice in producing a positive response. However, in young patients the electric pulp test was less reliable than CO 2 snow and dichlorodifluoromethane but more reliable than ethyl chloride and ice. The thermal agents were also compared for their ability to decrease intrapulpal temperature in vitro. The rate of temperature decrease was greater when CO 2 snow or dichlorodifluoromethane were applied to the tooth than in the case of either ethyl chloride or ice.

Tubular permeability to calcium hydroxide and to bleaching agents

Recent reports of clinical cases suggest that cervical root resorption may follow bleaching of endodontically treated teeth. Inflammatory root resorption may be arrested by placement of calcium hydroxide into the root canal. The dentinal tubules are assumed to be a possible route of action for both agents. pH Values of the medium surrounding the tooth after placement of bleaching agents and calcium hydroxide within the root canals were determined in this study. Thirty extracted single-rooted human teeth were divided into three equal groups. The pulp cavity of the experimental teeth was filled with either bleaching agents or calcium hydroxide. In the control group it was left empty. Dipping in paraffin sealed the access cavity and the apical foramina and isolated the teeth except at the cervical root surface. The teeth were placed in vials containing distilled water and the pH of the medium was measured after 1 h, 3 days, and 7 days following renewal of the medium. The level of the pH in the first group increased, indicating that the bleaching agents leaked from the root canal to the medium surrounding the teeth. The pH in other two groups did not change noticeably. The results suggest that bleaching agents may leak from the root canal toward the periodontal tissues but calcium hydroxide does not alkalinize the medium surrounding the teeth. Leakage of the bleaching agents through dentin may, therefore, be considered as a possible etiological factor that initiates an inflammatory process around the teeth that may be followed by cervical root resorption.

The Unpredictability of Seal After Post Space Preparation: A Fluid Transport Study

A root canal filling remaining after post space preparation is commonly expected to provide adequate seal. Coronal leakage of 30 endodontically treated teeth was measured before post space preparation using a fluid transport assay. In 10 of these teeth post space was prepared, using a two-step procedure, first to a remaining filling of 6 mm and then to 3 mm, with the leakage studied after each step. In 10 teeth the removal was done in one step to a remaining length of 3 mm. The other 10 teeth, with intact root canal fillings, served as controls and were tested twice for leakage. A significant difference was found between the sealing ability of intact fillings and that of partially removed ones (p < 0.05). The difference between the sealing ability of 3 and 6 mm remaining length group was not statistically significant. The lack of statistical differences between the 6 mm and 3 mm fillings was due to a great variability which existed among the 3 mm remaining fillings. These results suggest that 3 to 6 mm fillings provided a seal inferior to that of intact root canal fillings. Reduction of the fillings to 3 mm resulted in an unpredictable seal.

Antibacterial Efficacy of a New Chlorhexidine Slow Release Device to Disinfect Dentinal Tubules

Dentinal tubules of 27 cylindrical bovine root specimens were infected with Enterococcus faecalis. In nine specimens, 5% chlorhexidine was placed in a slow-release device (Activ Point) for 7 days, in another nine irrigation with 10 ml of 0.2% chlorhexidine was used, and the remaining nine served as positive control. Powder dentin samples obtained from within the canal lumina using ISO 025 to 033 burs were examined for the presence of vital bacteria by inoculating brain-heart infusion plates and counting colony forming units. Results were analyzed using analysis of variance and covariance with repeated measures. Heavy bacterial infection was observed at the layer close to the lumen in the control specimens, decreasing rapidly from layer to layer up to the deepest layer tested (400-500 microm), which contained several hundred colony forming units. Viable bacteria in each layer of dentin were significantly reduced with chlorhexidine irrigation solution (p < 0.01) and were completely eliminated with the chlorhexidine slow-release device (p < 0.01).

In vitro antibacterial activity of a glass ionomer endodontic sealer

The aim of this study was to evaluate the antibacterial activity of a recently introduced glass ionomer endodontic sealer, Ketac Endo (KE), compared to a commonly used ZOE-based endodontic sealer, Roths cement (RC). With the use of E. faecalis as a test organism, the agar diffusion test (ADT) and direct contact test (DCT) were performed. For the DCT, the sealers were mixed and placed on the side wall of microtiter plate wells. A 10 microL bacterial suspension was placed on the tested material samples 20 min, 24 h, and 7 days after mixing. Bacteria were allowed to directly contact the sealers for 1 h at 37 degrees C. Fresh media was then added and bacterial growth was measured every 30 min over 15 h. The results showed that in the ADT, freshly mixed KE exhibited a twofold greater inhibition zone than RC (p < 0.05); in the DCT, freshly mixed KE and RC completely inhibited bacterial growth. The 24-h and 7-day samples of KE showed no antibacterial activity, whereas RC continued to exhibit a strong effect with similar samples. It has been concluded that KE possesses a short-acting very potent and diffusable antibacterial activity, whereas RC extends its effect over 7 days after setting.

Intracanal pH Changes of Calcium Hydroxide Pastes Exposed to Carbon Dioxide In Vitro

It has been suggested that the main benefit of using calcium hydroxide as an intracanal medicament lies in its bactericidal effect, provided that the pH of the paste is above 12.5. The purpose of this study was to measure changes in the pH of several calcium hydroxide pastes sealed in root canals for 30 days. Sixty-two extracted, single-rooted human teeth were endodontically prepared using K-files up to size 60. The teeth were separated at random into six equal groups to be filled with either Calxyl, Hydrocalcium, or a paste made by mixing calcium hydroxide powder with either distilled water, camphorated p-monochlorophenol, local anesthetic solution, or Solvidont. Cavidentin was used to seal the coronal orifice of the teeth that were placed individually in vials containing 10 mL distilled water. Five vials of each group were exposed to air at room temperature, whereas the other five vials were exposed to carbon dioxide in a closed container. The pH of the paste in the root canal was measured after 30 days. There was no significant (p > 0.01) change in the pH (mean 13.11) of the pastes placed in teeth before and after exposure to air, whereas the pH of the pastes in teeth exposed to carbon dioxide was significantly (p < 0.01) reduced (mean 12.54). There was no significant difference in pH between the six preparations. After 30 days of exposure to carbon dioxide, they still maintained a purportedly bactericidal pH within the root canal.

Effects of thermal vitality tests on human dental pulp

Experiments were conducted to determine the effects of thermal pulp testing agents on the human dental pulp. Histological evaluation of the pulps of premolar teeth to which heated gutta-percha had been applied for up to 10 s revealed no evidence of injury. Teeth to which carbon dioxide (CO 2 ) snow was applied for as long as 5 min were found to have structurally intact pulps. When the thermal testing agents were applied to teeth in vitro, temperature in the region of the pulpodentinal junction did not reach noxious levels. This study indicates that assessment of tooth vitality with either heated gutta-percha or CO 2 snow does not jeopardize the health of the pulp.

Effect of intended treatment on anxiety and on reaction to electric pulp stimulation in dental patients.

Fear and anxiety are common emotional concomitants of acute pain that increase the perception of noxious events as painful. In the present study, 92 patients who were about to undergo various dental treatments (calculus removal, filling, root canal treatment, and extraction) were evaluated comparing the level of their dental anxiety and pain expectation from the intended treatment to their reaction to electric pulp stimulation. The data indicate that patients differ significantly in their dental anxiety levels and in their expectation to experience pain according to the following hierarchy (in descending order): extraction, root canal treatment, filling, and calculus removal. Anxiety and amount of pain expected from treatment correlated significantly with each other, but no simple correlations were found between anxiety and actual pain measures recorded after pulp stimulation.

Flare-ups after Endodontic Treatment: A Meta-analysis of Literature

The purpose of this study was to determine the frequency of flare-ups and to evaluate factors that affect it by using meta-analysis of results of previous studies. MEDLINE database was searched by using Entrez PubMed search engine and Medical Subject Headings (MeSH) search with EviDents Search Engine to identify the studies dealing with endodontic flare-up phenomenon. The search covered all articles published in dental journals in English from 1966-May 2007, and the relevancy of 119 selected articles was evaluated by reading their titles and abstracts, from which 54 were rejected as irrelevant and 65 were subjected to a suitability test. Six studies that met all the above mentioned criteria were included in the study. Average percentage of incidence of flare-ups for 982 patients was 8.4 (standard deviation +/-57). There were insufficient data to investigate the effect of the influencing factors.