ABSTRACT
The purpose of this study was to evaluate the effects of apical constriction (AC) diameter, irrigant flow rate, and needle tip design on apical pressure (AP) during the root canal irrigation. Five extracted human mandibular premolars were instrumented up to #35 (0.06 taper) using nickel-titanium rotary instruments. AC was determined at 1 mm from the apical foramen. Three needles with different tip designs (notched, side-vented, and flat) were placed 3 mm from AC. APs were measured with varying flow rates of 0.05, 0.1, 0.2, and 0.3 mL/s. The AC diameter of the teeth was enlarged to #40 and #45 (0.06 taper) successively, and the aforementioned measurement procedure was repeated (n=5). When the other conditions were controlled, AP increased with decreasing AC diameter or increasing irrigant flow rate, and the AP of flat needle was the highest, followed by notched, and side-vented needle (p0.35 mm, open-end (notched or flat) needles can be used to improve irrigant replacement in the apical portion using a flow rate of 0.05 mL/s.
Subject(s)
Humans , Bicuspid , Central Venous Pressure , Constriction , Dental Pulp Cavity , Needles , Tooth , Tooth ApexABSTRACT
The purpose of this study was to evaluate the effect of needle tip design and position, and irrigant flow rate on apical pressure (AP) during root canal irrigation. Five human mandibular premolars were instrumented up to #35 (0.06 taper) using nickel-titanium rotary instruments. Three different needles according to change of needle tip design (notched, side-vented, and flat) were positioned at the point of 1, 3, and 5 mm from the apical constriction (needle tip position). For each needle tip design and position, APs were measured with varying flow rates of 0.05, 0.1, 0.2, and 0.3 ml/s. When the other conditions were controlled, AP increased with decreasing needle tip position or increasing irrigant flow rate (p < 0.05). The AP of flat needle was the highest, followed by notched, side-vented needle for the same needle tip position and irrigant flow rate. The APs at needle tip position of 1 mm or with more than 0.1 ml/s flow rate were higher than central venous pressure (5.88 mmHg) for all conditions. Flat needle was not recommended for clinical use due to sharp increase of AP with changing needle tip position and irrigant flow rate. For safe and effective root canal irrigation, irrigant should be applied with the needle tip position of 3 mm and flow rate of less than 0.05 ml/s.
Subject(s)
Humans , Bicuspid , Central Venous Pressure , Constriction , Dental Pulp Cavity , NeedlesABSTRACT
Lumbar epidural anesthesia is useful in a variety of chronic benign pain syndromes, including lumbar radiculopathy, low back pain syndrome, spinal stenosis, and vertebral compression fractures. Given the increased number of epidural nerve blocks being performed, some have reported unexplained complications of a transient or permanent nature and with varying degrees of severity. However, no case has been reported of a broken epidural needle tip retained in the lumbar facet joint area. This represents the first reported case presentation of foraminal stenosis developing in a patient after a retained epidural needle tip.
Subject(s)
Humans , Anesthesia, Epidural , Constriction, Pathologic , Fractures, Compression , Low Back Pain , Needles , Nerve Block , Radiculopathy , Spinal Stenosis , Zygapophyseal JointABSTRACT
PURPOSE: To observe the degree of damage in a 30-gauge injection needle by observing the changes in needle tip following an intravitreal injection with the use of a scanning electron microscope. METHODS: The present study evaluated 11 injection needles collected following the use of an intravitreal injection of bevacizumab. Ten unused injection needles were selected as the control group. Needle examination was performed using a scanning electron microscope. RESULTS: Following 11 intravitreal injections, seven bent needle tips, two stubbed needle tips and two almost normal needle tips were observed following intravitreal injections. In the control group, a single damaged needle tip was observed. CONCLUSIONS: Significant damage to the needle tip was observed following intravitreal injection using a 30-gauge injection needle. The results indicate that needles should be manipulated carefully during an intravitreal injection. Additionally, in the control group where no procedures were performed, a single injection needle with damaged status was found. These results indicate that needles should be replaced in cases in which resistance is perceived during the procedure.