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Biomedical subjects

P K Sinha

Publications and source records attributed to P K Sinha.

At least 19 recordsLinked to original sources
PubMed2001

Anesthetic considerations in a patient with visceral leishmaniasis.

PURPOSE: To describe the anesthetic problems in a patient with visceral leishmaniasis undergoing general anesthesia. CLINICAL FEATURES: A 17-yr-old man with visceral leishmaniasis was booked for emergency appendectomy. He received parentral sodium stibogluconate 600 mg per day. The patient was pale, afebrile and had hepatosplenomegaly. Preoperative investigations showed a hemoglobin of 6.2 g.dL(-1), platelet count of 80 x 10(9).L(-1) and serum albumin of 2.1 g.dL(-1). The electrocardiogram and chest x-ray were normal. Anesthesia was induced with 100 microg fentanyl and 50 mg propofol iv and tracheal intubation was facilitated with 3 mg vecuronium iv. Maintenance of anesthesia was done with intermittent positive pressure ventilation using 50% nitrous oxide and 0.4% isoflurane in oxygen. Reversal of neuromuscular blockade was achieved with 1.0 mg neostigmine and 0.2 mg atropine iv. 50 mg tramadol iv every six hours was used for postoperative analgesia. The perioperative course was uneventful. CONCLUSION: Patients with visceral leishmaniasis have problems unique to them that may influence the anesthetic management. Of particular concern to an anesthesiologist are the presence of hematological abnormalities (anemia, leukopenia, thrombocytopenia), and hypoalbuminic malnutrition. The combination of low hemoglobin and thrombocytopenia may necessitate blood component therapy perioperatively. Drugs affecting coagulation should be used judiciously. Hypoalbuminemia may adversely affect the pharmacokinetics of agents that are highly protein bound. The anesthetic management in a patient with visceral leishmaniasis may be further complicated by the presence of coexisting infections like pneumonia and tuberculosis. Leishmaniasis is a recognized complication of infection with human immunodeficiency virus.

Adolescent↗
PubMed2001

The effect of saliva on shear bond strengths of hydrophilic bonding systems.

Failure of orthodontic bonded attachments and brackets is mostly attributed to contamination of the enamel surface. To overcome this problem, materials have been developed that purportedly overcome the moisture and contaminants present in the oral environment. This study compared the shear bond strengths of 2 lightcured hydrophilic bonding systems, Transbond XT with MIP (3M/Unitek, Monrovia, Calif) and Assure (Reliance Orthodontics, Itasca, Ill) with a hydrophobic bonding system, Transbond XT with XT primer (3M/Unitek). Comparison tests were conducted under 4 enamel surface conditions: (1) etched and dried; (2) etched and moistened with artificial saliva; (3) etched, primed, and moistened with artificial saliva; and (4) etched, primed, moistened with artificial saliva, and reprimed. In addition, an adhesive remnant index score was used to determine the amount of adhesive remaining on the tooth. Stainless steel brackets with mesh-backed pads (n = 144) were bonded to bovine teeth. Bond strength was then tested in shear using an Instron mechanical testing instrument. There were significant differences in the bond strengths among the products (P <.05), within surface treatments (P <.05), and among the different bonding materials in combination with various surface treatments (P <.05). Treatments 1 and 4 showed the highest mean bond strengths adhesive remnant index scores, whereas treatments 2 and 3 showed the lowest mean bond strengths and scores.

Acid Etching, Dental↗
PubMed2001

Effect of a subanesthetic dose of intravenous ketamine and/or local anesthetic infiltration on hemodynamic responses to skull-pin placement: a prospective, placebo-controlled, randomized, double-blind study.

Insertion of cranial pins for stabilization of the head can result in a marked hypertensive response, which may adversely affect cerebral hemodynamics. The efficacy of a subanesthetic dose of intravenous ketamine (0.5 mg/kg) and/or lidocaine infiltration (1%) at pin fixation sites before pinning was studied in a prospective, double-blind, placebo-controlled, randomized trial of 40 patients. The subjects were divided into four groups of 10. Patients belonging to the placebo and lidocaine groups received intravenous normal saline (NS), followed by local infiltration with NS at pin insertion sites in the placebo group and 1% lidocaine in the lidocaine group. Patients belonging to the ketamine and ketamine-lidocaine groups received intravenous ketamine followed by local infiltration with NS in the ketamine group, and lidocaine infiltration in the ketamine-lidocaine group. Heart rate (HR) and invasive mean blood pressure (MBP) were recorded before intravenous medication and then at various time intervals until 15 minutes after pin fixation. Intergroup comparison of MBP and HR by 2-way analysis of variance revealed a significant difference between the groups and various time points (P < .05). Post hoc analysis revealed maximum increase in MBP each hour in the placebo group. Mean blood pressure response in the ketamine group was similar to the placebo group. Significant attenuation of MBP and HR was observed in the lidocaine and ketamine-lidocaine groups (P < .05). A minimal increase in HR was observed in the lidocaine-ketamine group. The current study demonstrates maximum attenuation of hemodynamic responses when a subanesthetic dose of intravenous ketamine (0.5 mg/kg) is administered with 1% lidocaine infiltration.

Adolescent↗
PubMed2000

Longitudinal assessment of vertical and sagittal control in the mandibular arch by the mandibular fixed lingual arch.

The purpose of this investigation was to determine and quantify vertical changes in the position of the mandibular molars while maintaining arch perimeter with a fixed lingual arch. Twenty-three patients with a mean age of 10.4 +/- 0.6 years were selected to receive fixed lingual arch treatment as the only appliance in the mandibular arch. Average treatment time was 18.3 +/-+/- 0.6 months. Longitudinal records for 12 and 24 months of 24 individuals matched by ethnic origin, age, gender, and mandibular plane inclination were used as controls. Pretreatment and posttreatment cephalograms were used to determine positional changes. Statistically significant differences between the fixed lingual arch and control groups were found. The results of this investigation indicated that the mandibular fixed lingual arch is a useful tool to control the vertical development of the mandibular molars.

Cephalometry↗
PubMed2000

Evaluation of the Jones jig appliance for distal molar movement.

The purpose of this study was to determine the effects of the Jones jig appliance on distal movement of maxillary molars and reciprocal effects on premolars and maxillary incisors. Cephalometric radiographs before and after orthodontic treatment of 72 consecutively treated patients, 46 females and 26 males, were measured to define treatment changes attributed to the Jones jig. Comparative measurements were made on a matched sample of 35 patients (20 females and 15 males) treated with cervical headgear by the same clinician. Both series of patients were treated to correct an Angle Class II molar relationship. The molar correction in the Jones jig patients consisted primarily of molar distal movement. Dental, soft tissue, and skeletal changes were evaluated and compared for significant differences between techniques. The results from the Jones jig sample showed the mean maxillary first molar distal movement was 2.51 mm, with distal tipping of 7.53 degrees. The mean reciprocal mesial movement of the maxillary premolar was 2.0 mm, with mesial tipping of 4.76 degrees. The maxillary first molar extruded 0.14 mm; the maxillary premolar extruded 1.88 mm. The maxillary second molars were also moved distally 2.02 mm and tipped distally 7.89 degrees. The longitudinal assessment (initial to completion of orthodontic treatment) showed significant differences between the Jones jig sample and the cervical headgear sample for lower lip to E-line and SNA. The Jones jig sample showed a mean decrease in lower lip to E-line of 0.25 mm versus 1.20 mm (P < .0212) for the headgear sample. SNA decreased 0.40 degrees for the Jones jig sample versus 1.20 degrees (P < .0093) for the headgear sample. However, the Jones jig sample and cervical headgear sample did not show significant differences of the final position in either linear or angular measurements of the maxillary first molars and corresponding premolar-incisor anchor units. The Jones jig appliance demonstrated treatment results comparable with those of the sample treated with cervical headgear. The Jones jig sample demonstrated effective distal molar movement and maintenance of the Class I molar relationship. Advantages of the Jones jig include minimal dependence on patient compliance, ease of fabrication, and ease of buccal force application.

Adolescent↗
PubMed1999

Frictional resistance in orthodontic brackets with repeated use.

This study measured and compared the level of frictional resistance generated with a nonrepeated and repeated experimental design to evaluate whether the wear in the bracket slot will influence frictional resistance. Both 0.018 and 0.022 inch slot size edgewise brackets were tested in a specially designed apparatus. The frictional resistance was measured on an Instron Universal Testing Machine. A repeated measures ANOVA was used to determine differences among the 10 individual bracket wire specimens for each combination to study the influence of wear on static and kinetic frictional force. A paired t test (two-tail) procedure was used to compare the static and kinetic frictional forces in the nonrepeated and repeated study for each bracket slot, wire size, and bracket type. The results show that there was a distinct trend for the mean frictional force to be higher with the repeated use of the brackets.

Analysis of Variance↗
PubMed1999

Comparison of frictional resistance in titanium and stainless steel brackets.

This study measures and compares the level of frictional resistance generated between titanium and stainless steel brackets. Both 0.018 and 0.022 inch slot size edgewise brackets were tested with different sized rectangular stainless steel wires in a specially designed apparatus. The frictional resistance was measured on Instron Universal testing machine (Instron Corp, Canton, Mass) with a 10 pound load cell. The specimen population was composed of 180 brackets and 180 wire specimens. A completely randomized design (one way) ANOVA was used to test for significant differences among the three bracket/wire types in the 0.018 and 0.022 inch slot sizes. This was followed by the Student Newman Keuls Multiple Comparison of means ranking at P < .05 to determine differences between the different groups. The titanium brackets showed lower static and kinetic frictional force as the wire size increased, whereas stainless steel brackets showed higher static and kinetic frictional force as the wire size increased.

Analysis of Variance↗
PubMed1999

Comparison of load transmission and bracket deformation between titanium and stainless steel brackets.

This study measures the load transmitted and structural integrity of stainless steel and titanium brackets on application of torsional forces. Both 0.018 and 0.022 inch slot size edgewise brackets were tested in a specially designed apparatus that applied a torque value of 45 degrees. The load generated was measured by an Instron Universal Testing Machine at intervals of 15 degrees, 30 degrees, and 45 degrees of torque application. The structural stability of the brackets was evaluated by measuring the bracket slot width with a traveling stereoscopic microscope before and after the brackets were subjected to torsional forces. The specimen population was composed of 80 brackets and 80 wire specimens. An independent sample t test was used for comparison of mean load generated at 45 degrees of torque application. Repeated measures ANOVA (one-way) comparison was used to evaluate changes in load at different torque levels for the stainless steel and titanium brackets. A paired t test (two-tail) was used to determine the difference between initial and final bracket slot width at 45 degrees of torque applied for the two bracket types. The titanium brackets transmitted higher loads at 15 degrees and 30 degrees torque and lower load at 45 degrees torque on application of torsional forces in comparison to stainless steel brackets. The titanium brackets demonstrated superior dimensional stability compared to stainless steel brackets (P < .0001).

Analysis of Variance↗
PubMed1999

Ondansetron pretreatment to alleviate pain on propofol injection: a randomized, controlled, double-blinded study.

UNLABELLED: We used a randomized, controlled, double-blinded design to study the effect of ondansetron (OND) pretreatment on the pain produced by the IV injection of propofol. Eighty patients were randomly assigned to one of two groups: Group I received 2 mL of IV 0.9% saline pretreatment, and Group II received OND (4 mg in 2 mg/mL solution) pretreatment in the dorsum of the hand, followed by propofol 1 min later. Pain was reduced significantly in the OND group (P<0.05). Approximately one third of the patients in each group had myoclonic movements or skin rashes in the limb that received propofol. We conclude that the OND pretreatment may be used to reduce the incidence of pain on injection of propofol and to prevent postoperative nausea and vomiting. IMPLICATIONS: In a double-blinded, controlled study, IV ondansetron (4 mg) pretreatment was used to alleviate pain on injection of propofol. Ondansetron was successful in relieving pain without any adverse effect in a significant number of patients.

Adolescent↗