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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
PubMed1999

Efficacy of ondansetron in prophylaxis of postoperative nausea and vomiting in patients following infratentorial surgery: a placebo-controlled prospective double-blind study.

In a prospective double blind placebo-controlled study, 45 patients scheduled for infratentorial surgery were randomly allocated into two groups. Five patients were later excluded from the study because of various reasons. Out of 40 analyzable patients, 20 received IV Ondansetron (4 mg), whereas the other 20 received the matching placebo approximately 1 hour before the skin closure. After conclusion of surgery and tracheal extubation, all patients were monitored in the recovery room for post operative nausea and vomiting (PONV) for 48 hours. The incidence of PONV within the first 24 hours was found to be 50% and 10% in the placebo and ondansetron groups, respectively (p<0.05). After 24 hours, however, both groups were comparable in relation to the incidence of emesis. Rescue antiemetic (RAE) was required in nine (45%) patients in the placebo group and in two (10%) patients in the Ondansetron group (p<0.05). A significantly higher number of patients remained sedated postoperatively in the Ondansetron group than in the placebo group (p<0.05). One patient in the Ondansetron group had protracted diarrhea for 48 hours postoperatively. These results indicate that administration of IV Ondansetron (4 mg) 1 hour before skin closure effectively reduces PONV after infratentorial surgery, and does not have significant adverse effects.

Adolescent↗
PubMed1998

Orthodontists' assessment and management of patient compliance.

This study was designed to evaluate the use of predictors and methods of improving patient compliance. A survey of 118 items was developed by searching the literature for items that other researchers have found to be significant. The new questionnaire contained six sections. Sections 1 and 2 pertained to predictors of patient compliance; sections 3 and 4 related to methods of improving compliance. In section 5, the respondents were asked to evaluate patient personality traits that might be important in evaluating compliance, and in the last section, demographic background information on the respondents was collected. Questionnaires were mailed to 1,262 practicing orthodontists in the United States, and 429 responses were received. Patient-related items, such as desire for treatment and relationship with parents, were ranked as important factors motivating patients to comply. Verbal praise and communication were rated as important methods for improving compliance. Personality traits that orthodontists found to be predictive of patient compliance were: high self-esteem; obedient; accommodating; and self-confident. Patients' perceptions of their malocclusions, combined with their desire for orthodontic treatment, may be good indicators of compliance. Doctor-patient rapport and verbal praise may be useful ways to improve compliance.

Appointments and Schedules↗
PubMed1998

Effect of behavior modification on patient compliance in orthodontics.

The purpose of this study was to evaluate the effects of a reward system for improving patient compliance in orthodontic treatment. The sample consisted of 144 orthodontic patients (63 male, 81 female, average age 12.8 years), 6 to 12 months into their treatment. The sample was divided into above-average and below-average compliers, based on the orthodontic patient cooperation scale (OPCS). Each group was further divided into three subgroups: (a) a control group, which received only standard instructions; (b) an award group, which received compliance instructions and a written evaluation of compliance; and (c) a reward group, which received compliance instructions, a report card, and eligibility to receive rewards for adherent behavior. Two measurements of patient compliance were used: (1) the OPCS, which divided the sample into high and low compliers and was used to compare compliance before and after the 6-month experimental period; and (2) a clinical evaluation of compliance that was based on oral hygiene, appointment punctuality, appliance wear, and appliance maintenance. Evaluations were completed at each monthly appointment. Average compliance scores of above-average compliers showed no significant improvement with rewards. The average scores of patients with below-average compliance did not improve significantly. Only oral hygiene scores in the low compliance reward group were better than in the low compliance control group. Academic performance in school was found to be correlated (p < 0.001) with compliance. Above-average compliers remained above average in their compliance. The award/reward system may help motivate below-average compliers to comply with prescribed instructions.

Achievement↗
PubMed1997

In vitro evaluation of matrix-bound fluoride-releasing orthodontic bonding adhesives.

Sustained fluoride-releasing composite resins have the potential to prevent decalcification of enamel that may occur during the course of orthodontic treatment. The purpose of this study was to evaluate the potential of matrix-bound fluoride-releasing adhesives (MBF) for orthodontic use by comparing the shear bond strengths (in MPa) and remnant adhesive on debonding (ARI scores) of these resins with commercially available orthodontic adhesives. Two types of resins were evaluated in separate groups: The light-cured resins (group I) consisted of two light-cured MBF, designated resins LA and LB, and five nonfluoride releasing resins, designated LC, LD, LE, LF, and LG. The self-cured resins (group II) consisted of one MBF, designated resin SA, and six nonfluoride releasing resins, designated resins SB, SC, SD, SE, SF, and SG. These resins were used to attach upper right central incisor metal (foil mesh based) orthodontic brackets to 210 freshly extracted bovine incisors in groups of 15 each. Student-Newman-Keuls multiple comparison tests were performed at p < 0.05 to determine significant differences among the resin types. Resin LA was significantly higher in bond strength (mean = 27.4 MPa) compared with LD and LG (mean = 18.9, 10.7 MPa, respectively). Further, LA demonstrated a higher mean bond strength compared with LB, LC, LE, and LF (mean = 21.9, 24.1, 24.3, and 20.8 MPa, respectively). Resin LB had significantly lower ARI scores (mean = 0.33) compared with LF and LG (mean = 1.20 and 1.80). LA, LB, LC, LD, and LE (mean = 0.47, 0.33, 0.60, 0.73, and 0.73, respectively) were not significantly different in their ARI scores. Resin SB demonstrated significantly lower bond strength (mean = 17.2 MPa) compared with SC, SD, SE, SF, and SG (mean = 23.9, 23.7, 23.4, 23.8, and 22.9 MPa, respectively). Resin SA (mean = 19.0 MPa) was not significantly different in bond strength from SB, SC, SD, SE, SF, and SG. Resin SA demonstrated significantly lower ARI scores (mean = 0.73) compared with SD and SE (mean = 2.13 and 1.87). Resin SA had lower mean ARI scores compared with SB, SC, SF, and SG (mean = 1.00, 1.27, 1.13 and 0.87, respectively). Sustained fluoride-releasing (matrix-bound) orthodontic adhesive systems demonstrated bond strength and ARI scores that compared favorably with commercially available orthodontic adhesives.

Adhesiveness↗
PubMed1997

The effect of different bonding and debonding techniques on debonding ceramic orthodontic brackets.

Previous studies have indicated that different bonding and debonding techniques affect the removal or detachment of polycrystalline ceramic brackets that use a mechanical mechanism of bonding to resin. The delamination type debonding forces have been shown to be more effective, compared with twisting and tensile type forces. Further, polycrystalline brackets bonded by the indirect techniques debond leaving minimal filled resin on the tooth surface and hence cleanup and enamel damage are minimized. The purpose of this research was to compare the effects of three bonding and debonding techniques on debonding two types of ceramic brackets, using different modes of bonding. The monocrystalline bracket used the chemical and the polycrystalline bracket used the mechanical mechanisms for bonding respectively. Brackets were bonded to 180 freshly extracted bovine teeth, divided into two groups of 90 each, based on the bracket employed, i.e., monocrystalline and polycrystalline brackets. These brackets were bonded with the direct and two different indirect bonding methods: the conventional indirect method (modified Thomas) and the indirect technique that used a thermally cured resin. Each bonding group was further divided into three groups of 10, based on the type of debonding technique used, i.e., lift off, delamination, and twisting. The variables evaluated were bracket failure and remnant adhesive on debonding. The data were subjected to an analysis of variance to determine existence of significant differences, followed by multiple comparisons of means. Bracket failure or fracture was significantly affected, based on the bonding technique and the debonding technique for the monocrystalline at p < 0.0001 and the polycrystalline ceramic brackets at p < 0.001 and p < 0.05, respectively. Remnant adhesive was significantly affected by bonding and debonding techniques for the polycrystalline brackets at p < 0.0001. Remnant adhesive was significantly (p < 0.01) affected by the bonding technique for the monocrystalline brackets. The delamination debonding technique combined with the thermal-cured indirect bonding technique was shown to be a safe combination for debonding both types of ceramic brackets. Therefore both bonding and debonding techniques significantly affect bracket failure or fracture and remnant adhesive of ceramic orthodontic brackets during the debonding procedure.

Analysis of Variance↗
PubMed1997

Usefulness of short-term video EEG recording with saline induction in pseudoseizures.

OBJECTIVES: To study the usefulness of short-term recording of video electroencephalography (VEEG) as an outpatient procedure with placebo induction (PLIN) and intravenous saline in cases of pseudoseizures (Psz). MATERIAL AND METHODS: Fifty cases of suspected Psz were enrolled. They were divided into 2 groups: Group 1 consisted of patients with frank Psz, Group 2 those where diagnosis was uncertain. VEEG recording was done and 10 ml of saline used for placebo-induction. RESULTS: Of 50 patients, 24 (48%) were in Group 1 and 26 (52%) in Group 2. Fifteen (30%) had a spontaneous event during VEEG and 33% had an event only on PLIN. The diagnosis was confirmed in 60 %. In 24% of patients anti-epileptic drugs were discontinued. CONCLUSION: Short-term monitoring with VEEG using PLIN is a useful initial screening procedure and in patients where it is inconclusive, long term recordings may be done.

Adolescent↗
PubMed1997

Esthetic orthodontic appliances and bonding concerns for adults.

This article has described application of bonding procedures for adults in everyday practice. Depending on the materials and the technique employed, one can achieve satisfactory bonding. The techniques used to debond orthodontic brackets safely have been described. The bonded retainer, particularly in the mandibular arch, can easily be applied using the technique described. These retainers offer an advantage because of the high patient acceptance owing to convenience and esthetic reasons. Bonding on porcelain veneers and gold crowns has been described. Although silane pretreatment to the porcelain surface yields satisfactory results, the technique for bonding to gold has not yet been fully perfected.

Adult↗
PubMed1996

Perceived orthodontist behaviors that predict patient satisfaction, orthodontist-patient relationship, and patient adherence in orthodontic treatment.

Orthodontist-patient relationships have significant effects on the success of orthodontic treatment. The purpose of this study was to evaluate the effects of patient-perceived orthodontist behaviors on (a) patient perceived orthodontist-patient relationship, (b) patient satisfaction, and (c) orthodontist-evaluated patient adherence or compliance in orthodontic treatment. The sample consisted of 199 orthodontic patients, 94 boys and 105 girls, ages 8 to 17 years, who were recruited at the beginning of orthodontic treatment by a member of the research team who was not involved in treating the patients. The patients were asked to complete standardized questionnaires in a room away from the orthodontic clinic, 8 to 12 months into treatment. At the same time, the orthodontic resident treating each patient completed a standard instrument that evaluated patient compliance. Orthodontist behavior items such as politeness, friendliness, communicativeness, and empathy were evaluated by the patients. Stepwise multiple regression analyses (p < 0.05) showed that eight behaviors predicted perception of the orthodontist-patient relationship (final model R2 = 0.7930 and 0.7333) as well as patient satisfaction (final model R2 = 0.7952) and two behaviors predicted patient compliance (final model R2 = 0.0986). Of the 24 orthodontist behaviors, 22 were significantly correlated (p < 0.0001) with favorable orthodontist-patient relationship and patient satisfaction. Of the 24 behaviors, 10 were significantly correlated (five at p < 0.01 and five at p < 0.05) with patient compliance. Patient-perceived orthodontist behaviors are related to and predict (1) patient perceived orthodontist-patient relationship, (2) patient satisfaction, and (3) orthodontist-evaluated patient adherence or compliance.

Adolescent↗
PubMed1996

Frictional resistances in stainless steel bracket-wire combinations with effects of vertical deflections.

This research evaluated the effects of different bracket-wire combinations and second-order deflections on kinetic friction. Thirteen different brackets, six with 0.018 x 0.025 inch slots and seven with 0.022 x 0.028-inch slots were evaluated with six different sizes and shapes of stainless steel orthodontic wire, i.e., 0.016, 0.016 x 0.022, 0.017 x 0.025, 0.018, 0.018 x 0.025 and 0.019 x 0.026 inch for four second order deflections of 0.00, 0.25, 0.50, and 0.75 mm. The wires were ligated into the brackets with elastomeric modules. Bracket movement was implemented by means of an Instron universal testing instrument (RMO, Denver, Colo.), and frictional forces were measured by a tension load cell and recorded on an X-Y recorder (Hewlett-Packard, Anaheim, Calif.). Second-order deflection was created by a specially designed and machined testing apparatus that allowed two alternate pairs of the four total brackets to be offset in increments of 0.25 mm. The kinetic frictional force increased for every bracket-wire combination tested as the second-order deflection increased. Friction also increased with an increase in wire size, whereas rectangular wires produced greater friction than round wires. Bracket designs that limited the force of ligation on the wire generated less friction at low second-order deflections (0.00 and 0.25 mm).

Dental Stress Analysis↗
PubMed1996

The effects of exogenous prostaglandin E2 on root resorption in rats.

This study evaluated the amount and depth of root resorption associated with varying concentrations and frequencies of injectable, exogenous prostaglandin E2 (PGE2) in conjunction with orthodontic tooth movement in rats. The sample consisted of 155 maxillary right and left first molars from 88, 8-week old, male Sprague-Dawley rats. The animals were divided into three control groups and two experimental groups. The control animals were divided into one nonappliance and two appliance groups. The experimental animals were divided into 2- and 4-week experimental time periods that were further subdivided based on single and weekly injection intervals of PGE2 and four different injectable concentration levels, i.e., 0.1, 1.0, 5.0, and 10.0 micrograms. A fixed orthodontic appliance was ligated between the maxillary incisors and maxillary first molars with closed-coil nickel-titanium springs. The appliance had an initial activating force of 60 gm. Serial histologic sections of the mesial root of the maxillary first molar were made, and a quantitative histomorphometric analysis of root resorption on the mesial and distal surfaces was performed. This study demonstrated increased root surface resorption when using exogenous PGE2 injections to enhance orthodontic tooth movement over a 2-week period with increasing root resorption on the mesial surface as compared with the distal surface in PGE2 treated teeth. No differences in root resorption were found with either multiple injections or increasing concentration in the 4-week experimental group. Local injection of PGE2 appeared to have no effect on the number or depth of resorption lacunae in either the 2- or 4-week groups.

Analysis of Variance↗
PubMed1996

Tomographic assessment of temporomandibular joints in patients with malocclusion.

There is a paucity of information on the morphological assessment of the temporomandibular joint in relation to varying skeletal and dental relationships. The purpose of this study was to evaluate the morphologic relationship of the condyle and fossa in patients with different malocclusions and skeletal relationships. Pretreatment records of 232 orthodontic patients, 95 males and 137 females, of Caucasian descent and ranging in age from 9 years 4 months to 42 years 6 months, were examined. Records included dental casts, lateral cephalometric radiographs, hand-wrist radiographs, and corrected tomograms of right and left TM joints. Nonconcentricity and mild asymmetry of the condyle-fossa relationship were commonly observed. The left condyle was found to be more anteriorly positioned than the right, with the mean percentage of joint space being 6.93% on the left side and -1.24% on the right. Skeletal and dental Class III patients demonstrated significantly more anteriorly positioned condyles (P < 0.05). There were no significant differences in condylar position between Class I and Class II groups based on ANB or Angle's classification. Further, no significant difference in condylar position was observed between groups based on overbite or crossbite.

Adolescent↗
PubMed1996

Fracture strength of ceramic brackets during arch wire torsion.

This study evaluated the fracture strengths of eight new vintage ceramic brackets with application of torsional forces. Palatal root torque was applied at the distal side of right maxillary central incisor brackets with 0.022-inch slots by means of a 0.0215 x 0.027-inch rounded edge stainless steel arch wire. A specially designed apparatus that attached to an Instron machine was used to test the ceramic brackets. The amount of torque, degrees of torsion at failure, and fracture locations were measured. The monocrystalline bracket did not break when the torquing test was applied; the portion of the wire outside the slot of the bracket twisted on itself. The mean torquing forces at failure ranged from 5755.2 gm-mm to 9316.5 gm-mm and could be separated into three statistically different groups. The mean torsional rotation at fracture ranged from 32.7 degrees to 68.1 degrees for the polycrystalline brackets. The results suggested that all the brackets studied were sufficiently strong to withstand the commonly accepted magnitudes of arch wire torquing forces. The present investigation showed higher angulation values for all the brackets than those reported by Holt who used the same apparatus with older style brackets.

Analysis of Variance↗