Influence of glass fibre post cementation depth on dental root fracture.

INTRODUCTION: Glass fibre posts that are newer and have better properties are gaining more popularity than metal posts. However, there is no consensus about the optimal cementation depth of glass fibre posts. In our study, we have attempted to assess fracture resistance of roots restored with glass fibre posts cemented at different root depths. MATERIALS AND METHODS: Specimens were formed with peeso reamers and a special reamer adapted for the cementation of glass fiber posts at different depths. Glass fibre posts were cemented using self-etching cement: in group 1 - at the depth of 2/3 of the working length of the root canal (11 mm), in group 2 - at the depth of 1/2 of the working length of the root canal (7.5 mm) and in group 3 - at the depth of 1/3 of the working length of the root canal (5 mm). Dental roots were standardized by preparing their walls to equal measurements with a mill. Specimens were embedded on a metal plate at a 45° angle and were vertically pressed with a hydraulic press in buccolingual direction. Fracture force was recorded in Newton (N) to the breaking point. RESULTS: After data analyses with ANOVA and T-test software, the null hypothesis was confirmed: there was no statistically significant difference among the results of all 3 groups (P >0.05). CONCLUSION: The cementation depth of the glass fibre posts that we studied has no influence on root fracture resistance.

The Reliability of Panoramic Radiography Versus Cone Beam Computed Tomography when Evaluating the Distance to the Alveolar Nerve in the Site of Lateral Teeth.

BACKGROUND The aim of this study was to compare the reliability of panoramic radiography (PR) and cone beam computed tomography (CBCT) in the evaluation of the distance of the roots of lateral teeth to the inferior alveolar nerve canal (IANC). MATERIAL AND METHODS 100 PR and 100 CBCT images that met the selection criteria were selected from the database. In PR images, the distances were measured using an electronic caliper with 0.01 mm accuracy and white light x-ray film reviewer. Actual values of the measurements were calculated taking into consideration the magnification used in PR images (130%). Measurements on CBCT images were performed using i-CAT Vision software. Statistical data analysis was performed using R software and applying Welch's t-test and the Wilcoxon test. RESULTS There was no statistically significant difference in the mean distance from the root of the second premolar and the mesial and distal roots of the first molar to the IANC between PR and CBCT images. The difference in the mean distance from the mesial and distal roots of the second and the third molars to the IANC measured in PR and CBCT images was statistically significant. CONCLUSIONS PR may be uninformative or misleading when measuring the distance from the mesial and distal roots of the second and the third molars to the IANC.

Antimicrobial activity of silver and gold in toothpastes: A comparative analysis.

OBJECTIVE: In this study, we compared the antimicrobial activity of identical toothpastes differing only in silver or gold nanoparticles against the activity of one of the common toothpastes containing a chemical active ingredient. We also compared the active concentrations of the toothpastes. METHODS: For this study, we selected "Royal Denta" toothpastes containing silver and gold particles, and the "Blend-A-Med Complete" toothpaste containing zinc citrate as the active ingredient. We used 8 standard microorganism cultures on the basis of their individual mechanisms of protection. The antimicrobial activity of each studied preparation was evaluated at 9 concentrations. RESULTS: Most effective against gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis) was the "Silver Technology" ­ MIC was 0.004-0.0015 g/mL. Neither "Silver Technology" nor "Orange and Gold Technology" had any effect on Escherichia coli or Proteus mirabilis. Antimicrobial activity against the motile bacterium Proteus mirabilis was observed in "Silver Technology", "Orange and Gold Technology", and "Blend-A-Med Complete" ­ the MIC was 0.015 g/mL or lower. No antimicrobial activity against Candida albicans fungus at the studied concentrations was observed in the "Orange and Gold Technology". The toothpaste "Blend-A-Med" demonstrated the most effective antimicrobial activity - the MIC of 0.0015 g/mL and 0.015 g/mL inhibited Staphylococcus aureus and Enterococcus faecalis, respectively, and the MIC of 0.15 g/mL inhibited the growth of the bacteria Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, and fungus Candida albicans. CONCLUSIONS: Silver in toothpaste has a greater antimicrobial effect than gold, but its effect is still inferior to that of a chemical antimicrobial agent.

Viability changes: microbiological analysis of dental casts.

BACKGROUND: This study evaluated the survival of the most prevalent oral bacteria and fungi (Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, and Candida albicans) in dental casts, and compared changes in the amounts of these microorganisms at different time intervals to determine how long dental casts may pose threat to the health of dental personnel and patients. MATERIAL AND METHODS: When manufacturing the casts, regular water was replaced with sterile distilled water, where suspensions of the studied bacteria or the fungus at certain concentrations were prepared. When the dental casts were fully set (solidified), plaster shavings were examined immediately after the contact of the studied microorganism with the plaster, as well as after 1, 2, 24, 48, 72, 96, and 120 hours. Following that, we measured how the amount of the studied bacteria and fungi in 1 gram of the plaster changed within the studied period of time. RESULTS: Klebsiella pneumoniae survived in plaster for up to 4 days, and the reduction in the number of these bacteria became statistically significant after 1 day (p<0.05). Staphylococcus aureus remained viable in plaster for up to 4 days, and the number of these bacteria dropped after 1 day (p<0.05). Escherichia coli disappeared after 2 days, and a reduction was already observed after 2 hours (p<0.05). Candida albicans in plaster models died within 2 days, and a reduction in their number was observed after 1 day (p<0.05). CONCLUSIONS: The microorganisms did not multiply in the gypsum casts and their number significantly dropped instead of increasing.

The effect of cleaning substances on the surface of denture base material.

BACKGROUND: The aim of this study was to evaluate the effect of substances used for hygienic cleaning of dentures on the surface of the denture base material. MATERIAL AND METHODS: Meliodent Heat Cure (Heraeus-Kulzer, Germany) heat-polymerized acrylic resin was used to produce plates with all the characteristics of removable denture bases (subsequently, "plates"). Oral-B Complete toothbrushes of various brush head types were fixed to a device that imitated tooth brushing movements; table salt and baking soda (frequently used by patients to improve tooth brushing results), toothpaste ("Colgate Total"), and water were also applied. Changes in plate surfaces were monitored by measuring surface reflection alterations on spectrometry. Measurements were conducted before the cleaning and at 2 and 6 hours after cleaning. RESULTS: No statistically significant differences were found between the 3 test series. All 3 plates used in the study underwent statistically significant (p<0.05 changed)--the reflection became poorer. The plates were most affected by the medium-bristle toothbrush with baking soda--the total reflection reduction was 4.82 ± 0.1%; among toothbrushes with toothpaste, the hard-type toothbrush had the greatest reflection-reducing effect--4.6 ± 0.05%, while the toothbrush with table salt inflicted the least damage (3.5 ± 0.16%) due to the presence of rounded crystals between the bristles and the resin surface. Toothbrushes with water had a uniform negative effect on the plate surface - 3.8 9 ± 0.07%. CONCLUSIONS: All substances used by the patients caused surface abrasion of the denture base material, which reduced the reflection; a hard toothbrush with toothpaste had the greatest abrasive effect, while soft toothbrushes inflicted the least damage.

In vitro investigation of the integration depth of oral fluids and disinfectants into alginate impressions.

THE OBJECTIVE: The objective of this work is to prove that oral cavity fluids diffuse into alginate mass of impressions. In addition, the information is presented on the subject that disinfectants used for alginate impressions disinfection not only diffuse into alginate mass but penetrate deeper than oral cavity fluids. MATERIALS AND METHODS OF THE STUDY: Three examination groups were formed for the research, the results of which evidenced how deeply oral cavity fluids and disinfectants 'Alpha Guard GF' and 'Orbis' could possibly diffuse into alginate impression material 'Kromopan 100'. In the first examination group ten impressions from the upper jaw dental arch and mucosa were taken, firstly colouring oral cavity fluids with a special colouring tablet MIRA-2-TON (Hager Werken). Cuts were randomly selected from impressions and scanned aiming to establish the depth of the coloured oral cavity fluid penetration. In the second and the third examination groups taken alginate impressions were accordingly soaked in 'Alpha Guard GF' and 'Orbis' with pigment and later randomly selected cuts were scanned in the same manner as in the first research group. RESULTS. The research results establish that coloured dental cavity fluids maximum diffuse into alginate impression is up to 540 microm with the presence of 95% of discolouring while disinfectants 'Alpha Guard GF' and 'Orbis' accordingly diffuse into alginate mass up to 710 microm and 870 microm with the presence of 95% of discolouring. CONCLUSIONS. The results obtained show that disinfectants using them according to the recommendations of a manufacturer, diffuse into alginate mass deeper than oral cavity fluids at the time of impressions taking.

[Staphylococcus aureus prevalence among preschool- and school-aged pupils]. / Staphylococcus aureus paplitimas tarp ikimokyklinio ir mokyklinio amziaus vaiku.

OBJECT: To determine the prevalence and incidence of Staphylococcus aureus strains among preschool- and school-aged pupils and susceptibility of these strains to antimicrobial materials. MATERIAL AND METHODS: A study of 243 preschool- and 300 school-aged pupils was conducted during 2003-2004. Identification of Staphylococcus aureus was made with plasmacoagulase and DNase tests. The resistance of Staphylococcus aureus to antibiotics, beta-lactamase activity, phagotypes, and phage groups were determined. The isolated Staphylococcus aureus strains were tested for resistance to methicillin by performing disc diffusion method using commercial discs (Oxoid) (methicillin 5 microg per disk and oxacillin 1 microg per disk). RESULTS: A total of 292 (53.8%) Staphylococcus aureus strains were isolated and identified (113 (46.5%) from preschool- and 179 (59.7%) from school-aged pupils). The prevalence of Staphylococcus aureus strains among preschool-aged pupils varied from 46.5% to 47%. It increased to 59.0% (P>0.05) among schoolchildren aged from 11 to 15 years and to 73.0% (P<0.001) among schoolchildren aged from 16 to 19 years. Six methicillin-resistant Staphylococcus aureus strains were isolated: two (1.8%) of them were from preschool-aged and four (2.2%) from school-aged pupils. The prevalence of Staphylococcus aureus strains with beta-lactamase activity increased from 70.7 to 76.6% in preschool-aged pupils, and it varied from 72.0 to 79.0% in school-aged pupils (P>0.05). Staphylococcus aureus strains of phage group II (32.2-43.4%) were prevailing; nontypable Staphylococcus aureus strains made up 19.2-33.6%. CONCLUSIONS: The prevalence of Staphylococcus aureus among preschool-aged children is 41.7 to 48.8%, and it increases among 9th-12th-grade pupils (73.0%, P<0.001). Some Staphylococcus aureus strains (2.1%) were resistant to methicillin. Staphylococcus aureus strains of phage group II (39.0%, P<0.05) are most prevalent among preschool- and school-aged pupils. Pupils were colonized with methicillin-resistant Staphylococcus aureus strains belonging to phage group III phagotype 83A and 77.

Effectiveness evaluation of different suction systems.

Microorganisms of the patient's oral cavity and his/her blood and saliva may cause different air-borne and blood-borne infectious diseases among odontologists and their assistants who work with patients. Quantitative analysis and spatial distribution analysis of the environmental spread of oral liquid and cooling liquid mixture were performed during this study. Effectiveness of suction systems of four types was evaluated: without suction, using a small-size suction pump alone, using a small-size and large-size suction pumps, using a small-size suction pump together with an experimental extra-oral aspirator. Quantitative changes of the water aerosol, which enters the environment during the preparation of teeth, were determined in respect of the used suction systems. The small-size pump system together with an experimental extra-oral suction system eliminated best the aerosol formed during the preparation.