pH of pus collected from periapical abscesses.

AIM: To determine the pH of pus collected from periapical abscesses. METHODOLOGY: Forty patients (Male = 17/Female = 23) between the ages 17 and 37 years, each with a periapical abscess and with no relevant medical history, were recruited. All the participants had moderate-to-severe pain on percussion accompanied by localized or generalized swelling. At least 1 mL of pus was aspirated from each participant using a No 20 gauge needle. A pH meter was used to define the pH of the pus immediately following aspiration. RESULT: The mean pH of pus from the periapical abscesses of patients was 6.68 +/- 0.324 with a range between 6.0 and 7.3. There was no statistically significant difference in pH by gender or age. CONCLUSION: The mean pH of pus from periapical abscesses was generally acidic, but some samples (two female and three male) were neutral and some samples (four female and one male) were alkaline.

The effect of pH on surface hardness and microstructure of mineral trioxide aggregate.

AIM: To evaluate the surface microhardness of mineral trioxide aggregate (MTA) specimens following exposure of their surface to a range of acidic environments during hydration. In addition, the morphological microstructure features of samples were studied by scanning electron microscopy (SEM). METHODOLOGY: White ProRoot MTA (Dentsply Tulsa Dental, Johnson City, TN, USA) was mixed and packed into cylindrical polycarbonate tubes. Four groups, each of 10 specimens, were formed using a pressure of 3.22 MPa and exposed to pH 4.4, 5.4, 6.4 and 7.4, respectively, for 4 days. Vickers microhardness of the surface of each specimen was measured after exposure. Four groups of two specimens were prepared and treated in the same way prior to qualitative examination by SEM. Data were subjected to one-way anova and post hoc Tukey's test. RESULT: The greatest mean surface hardness values (53.19 +/- 4.124) were observed following exposure to pH 7.4 with the values decreasing to 14.34 +/- 6.477 following exposure to pH 4.4. The difference between these values at the 95% CI (33.39-44.30) was statistically significant (P < 0.0001). There were no distinct morphological differences between groups in terms of the internal microstructure. However, a trend was observed that the more acidic the solution, the more extensive the porosity of the specimens. CONCLUSION: Under the conditions of this study, surface hardness of MTA was impaired in an acidic environment.

An in-vitro comparison of the radiographic and actual gutta-percha terminus.

The purpose of this study was to investigate the difference between the radiographic gutta-percha terminus and the actual gutta-percha terminus of human molars by comparing radiographic obturation results with actual obturation results. Forty maxillary palatal roots and 50 mandibular distal roots were randomly selected from a population of 540. They were then mounted in stone and radiographed. Conventional endodontic therapy was completed using stainless-steel K files and lateral condensation. Each radiographic gutta-percha terminus was evaluated under 4.5x magnification by three examiners following the completion of root canal therapy. These results were recorded. Each tooth was then removed from its mounting, and the actual gutta-percha terminus was evaluated under 4.5x magnification. These results were recorded and compared to the radiographic gutta-percha terminus results. In all 90 teeth examined, the actual gutta-percha terminus was equal to or longer than the radiographic gutta-percha terminus. In the 50 mandibular distal roots, the actual gutta-percha terminus averaged 0.645 mm longer than the radiographic gutta-percha terminus. In the 40 maxillary palatal roots, this difference measured 0.6375 mm.

Comparison between a hand stainless-steel K file and a rotary NiTi 0.04 taper.

Straightening of curved canals is one of the most common procedural errors in endodontic instrumentation. It can lead to ledging, perforation, and stripping of the canal. The problem is commonly encountered when root canal preparation is performed in curved molars. The purpose of this study was to compare the results of root canal preparation by undergraduate dental students using traditional stainless-steel 0.02 taper K files to results obtained using rotary nickel-titanium 0.04 taper files. One hundred ninety six extracted teeth comprising maxillary and mandibular first molars were used. Preoperative and postoperative radiographs of each tooth were taken. Graduate endodontic residents evaluated the radiographs according to the evaluation criteria used by the endodontic department. The presence of errors--such as stripping, perforation, ledging, transportation, zipping, and instrument breakage--was recorded by examining the radiographs.

Gutta-percha: a look at the need for sterilization.

Many have argued that the prevention of contamination becomes a problem when gutta-percha cones are used to obturate the root canal space. This study evaluated the extent of contamination of commercially available gutta-percha cones taken directly from the manufacturer's box. Results show that if gutta-percha is not intentionally contaminated, there is no need for chemical decontamination before obturation.