Do separated instruments affect pH levels when using calcium hydroxide as intracanal dressing?

BACKGROUND: The aim of this study was to evaluate the effect of intracanal separated instruments with different lenghts on periapical pH levels using calcium hydroxide (CH) as an intracanal medicament. MATERIALS AND METHODS: In total, 60 teeth were used. Following root canal preparation, teeth were divided into four groups (n = 15). In Group 1, 2 mm and in Group 2, 4 mm weakened from the tip of Revo-S NiTi SC2 (Micro-Mega, Besancon, France) instruments were separated in the apical portion of root canals. In Group 3, there was no separated instrument. CH paste was placed in the first three groups. In Group 4, there was no separated instrument or CH paste. Teeth were placed in containers with deionized distilled water. After 1 h and 1, 2, 7, 15, and 30 days, the pH of the solution was measured. RESULTS: At 1 h, Group 3 showed a significantly higher pH than Groups 1 (2 mm) and 2 (4 mm; P < 0.05). At the same time point, Group 1 (2 mm) showed a higher pH than Group 2 (4 mm) without significance. At 1, 2, 7, 15, and 30 days, Group 2 (4 mm) showed a significantly lower pH than Groups 1 (2 mm) and 3 (P < 0.05). At the same time points, Group 1 (2 mm) showed a lower pH than Group 3 without significance. CONCLUSIONS: Separated instrument may affect the rise in periapical pH level when using CH as the intracanal dressing. Therefore, 4 mm of separated instrument in the apical third showed a significant effect.

Comparison of warm vertical compaction and cold lateral condensation of α, ß gutta-percha and resilon on apically extruded debris during retreatment.

BACKGROUND: This study was performed to evaluate the amount of apically extruded debris removed from a root canal filled with cold lateral condensation (CLC), and warm vertical compaction (WVC) techniques, using b or a phase gutta-percha with AH-Plus (Dentsply DeTrey, Konstanz, Germany) or Resilon (Resilon Research LLC, Madison, WI) with RealSeal SE (SybronEndo, Amersfoort, The Netherlands). MATERIALS AND METHODS: About 100 human incisor teeth were prepared with a #25.06 NiTi rotary system and divided into five groups according to the filling material used: Group 1: CLC (gutta-percha, AH-Plus); Group 2: WVC (b phase gutta-percha, AH-Plus); Group 3: WVC (a phase gutta-percha, AH-Plus); Group 4: CLC (Resilon, RealSeal SE); and Group 5: WVC (Resilon, RealSeal SE). Extruded debris during the retreatment procedure was collected in preweighed Eppendorf tubes. The times required for retreatment were recorded. RESULTS: The amount of debris extrusion was significantly greater with WVC than CLC in the gutta-percha and Resilon groups (P < 0.001). Using a phase gutta-percha resulted in significantly more debris extrusion than b phase gutta-percha (P < 0.001). In the WVC groups, Resilon caused significantly more debris extrusion than gutta-percha (P < 0.05). Retreatment was faster for CLC than WVC (P < 0.05). CONCLUSIONS: In the retreatment procedure, the amount of apically extruded debris and retreatment duration were dependent on the type of obturation material and technique used.

A DNP investigation of pi and final sigma transitions for nitroxide spin probes at 1.53 mT.

A weak field DNP study of 4-hydroxy-2,2,6, 6-tetramethyl-1-piperidinyloxy (4-hydroxy-TEMPO), 4-amino-2,2,6, 6-tetramethyl-1-piperidinyloxy (4-amino-TEMPO), and 2, 2-Di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) free radicals invarious solvents was performed at 1.53 mT using a doubleresonance spectrometer. pi transitions, in which the RF fieldhas a component perpendicular to the static magnetic fieldB0, and final sigma transitions, in which the RF field has a component parallel to B0, were recorded. In order to observe thefinal sigma transitions a new probe head was designed. The final sigma transitions were obtained at the frequencies expected from theoretical calculations. However, the results obtained for the observed enhancements deviated from the values expectedtheoretically.

Ossified chronic subdural hematoma: case report.

A case of ossified chronic subdural hematoma is presented in a 13-year-old male in whom the mass was surgically removed. His neurological deficits continued afterward but were less severe.

Ultrasound diagnosis of liver hydatid disease.

A clinical study of 42 patients with hydatid disease was carried out using a real-time gray scale B-scanner. All cases were confirmed surgically. The ultrasound characteristics of the hydatid cysts were classified into three groups: Type I, simple hydatid cyst (19 of the 42 cases), type II, hydatid cyst with a disrupted wall and septa (14 cases), and type III, hydatid cyst with a heterogeneous echo pattern (9 cases). It was concluded that ultrasound classification of the cysts increases diagnostic accuracy. However, if a hydatid cyst becomes secondarily infected these typical changes are lost and the ultrasound diagnosis may then become more difficult. Periodic examinations should be performed with ultrasound after surgery.