Search PubMed⌕ Search

Biomedical subjects

P L Sadowsky

Publications and source records attributed to P L Sadowsky.

At least 19 recordsLinked to original sources
PubMed2000

The perception of optimal profile in African Americans versus white Americans as assessed by orthodontists and the lay public.

This study was designed to assess the perceived optimal profiles of African Americans versus white Americans. A survey was conducted using profile silhouettes of 30 African American and 30 white patients, ranging in age from 7 to 17 years. Twenty white orthodontists, 18 African American orthodontists, 20 white laypersons, and 20 African American laypersons evaluated the profiles. The preference of each rater for each of the 60 profiles was scored on an attached visual analog scale. Eighteen cephalometric variables were measured for each profile, and statistical analyses were performed on the profiles that had a mean rating of 60 or greater from an analog scale of 0 to 100. The results show the following 6 cephalometric variables were significant: Z-angle, skeletal convexity at A-point, upper lip prominence, lower lip prominence, nasomental angle, and mentolabial sulcus. All raters preferred the African American sample to have a greater profile convexity than they preferred for the white sample. The raters preferred the African American sample with upper and lower lips that were more prominent compared with the white sample. However, only the choice of the African American orthodontists for the African American sample was significantly different for this parameter. The white orthodontists gave the highest mean scores for the profile chosen, whereas the African American laypersons gave the lowest scores.

Adolescent↗
PubMed1999

An in vitro evaluation of a metal reinforced orthodontic ceramic bracket.

The objectives of the present study were to measure and compare the bond strength and failure sites of a currently available ceramic bracket (Transcend 3M-Unitek) with the new metal reinforced ceramic bracket (Clarity 3M-Unitek) and to evaluate the amount of composite left on the tooth using the Adhesive Remnant Index in the teeth that were debonded with pliers recommended for this purpose. In addition, the presence or absence of enamel damage after debonding was also assessed. One hundred and twenty extracted premolar teeth were divided into 4 groups of 30 each. Two groups of 30 teeth had Transcend 6000 brackets bonded, and the other 2 groups had Clarity brackets bonded. Shear bond strength was carried out on 30 Transcend 6000 brackets and 30 Clarity brackets, whereas the other 2 groups of 30 teeth bonded with Transcend 6000 and Clarity brackets were debonded with debonding pliers recommended by the manufacturer of both ceramic brackets. The mean shear bond strength of the Clarity brackets was 13.27 MPa, whereas that of the Transcend 6000 was 21.19 MPa. Both brackets failed mostly at the bracket-adhesive interface (75%), indicating a possible reduction of the chances of enamel damage. Six of the premolars, bonded with Transcend 6000 brackets and debonded with the plier, showed an increase in the number or length of enamel cracks as evaluated by an optical microscope (Micro-Vu); one premolar, bonded with Clarity brackets and debonded with the pliers, showed an increased enamel crack length. Gross enamel damage, assessed by enamel dislodgment, was not evident in any specimen. Results of this study suggest that the new metal reinforced ceramic bracket (Clarity) may be recommended for clinical use because of its acceptable shear bond strength and possible reduced chances of enamel damage during bracket removal.

Bicuspid↗
PubMed1999

Three-dimensional reconstruction system for imaging of the temporomandibular joint using magnetic resonance imaging.

This study was undertaken to develop a three-dimensional reconstruction system using magnetic resonance (MR) images in order to visualize three-dimensional images of the temporomandibular joint (TMJ) including the disk. The computerized reconstruction program (written using Visual Basic for Windows, Microsoft Corp.) could reliably generate three-dimensional images of the TMJ. Image processing techniques made the tracing of images unnecessary, reduced complex human manipulation and associated measurement errors. This system, capable of treating fifty thousand pixels or more, generates smooth three-dimensional images of the TMJ.

Data Display↗
PubMed1998

Craniofacial growth and the timing of treatment.

The timing of orthodontic treatment to achieve an optimal outcome is an issue of paramount importance to the clinical orthodontist. In this article I highlight those facts we know, list some we do not know for certain, and discuss aspects of the decision-making process in orthodontics. With increased insight into proven data and decisionmaking processes, the clinical orthodontist should be better able to appropriately time orthodontic treatment.

Adolescent↗
PubMed1998

An in vivo comparison between a visible light-cured bonding system and a chemically cured bonding system.

Direct bonding of brackets has become a routine procedure in clinical orthodontics. Many techniques and materials are currently advocated and used, the most recent being light-cured composites. Advantages of the light-cured systems are their relative ease of use, improved bracket placement, and more rapid set of the composite. For a new system to be clinically viable, it must possess properties that are at least as reliable as existing systems. The purpose of this longitudinal clinical study was to evaluate and compare the rate of success and/or failure between a visible light-cured bonding material (Sequence) and a chemically cured bonding material (System 1+), using both systems in every patient. Contralateral quadrants were bonded with each system respectively. A total of 32 patients were followed for a mean period of 11 months (range of 3 to 21 months), with a total of 531 brackets bonded, 265 with visible light-cured and 266 with chemically cured resins. Failures for each system were recorded and failure rates calculated. The failure rate of the visible light-cured composite was 11.3% and that of the chemically cured composite was 12%. A Chi-squared (chi2) test did not reveal any statistically significant differences between the failure rates of the two systems, (chi2 = 0.014, df-1, P > 0.9).

Acid Etching, Dental↗
PubMed1998

An evaluation of two VTO methods.

A sample of 34 growing Class II patients was used to assess the reliability of manual and computer-generated visual treatment objectives (VTOs) when compared with the actual treatment results. Skeletal, dental, and soft tissue measurements were performed on the VTO and on the posttreatment tracings. Using paired t-tests and Pearson correlation coefficients, comparisons were made between the VTO and posttreatment tracings. Both the manual and computer VTO methods were accurate when predicting skeletal changes that occurred during treatment. However, both methods were only moderately successful in forecasting dental and soft tissue alterations during treatment. Only slight differences were seen between the manual and computer VTO methods, with the computer being slightly more accurate with the soft tissue prediction. However, the differences between the two methods were not judged to be clinically significant. Overall, the prediction tracings were accurate to only a moderate degree, with marked individual variation evident throughout the sample.

Adolescent↗
PubMed1997

Evaluation of video imaging prediction in combined maxillary and mandibular orthognathic surgery.

The purpose of this study was to evaluate the accuracy of the soft tissue profile "line drawings" predicted by Quick Ceph Image in combined maxillary and mandibular orthognathic surgical procedures. Preoperative (mean = 27.7 days presurgical) and posttreatment (mean = 11.5 months postsurgical) lateral cephalograms of 40 white patients (10 males and 30 females) who had completed treatment that involved orthodontics, one-piece LeFort I osteotomy, and mandibular advancement by bilateral sagittal split osteotomy with or without genioplasty were used in the study. Forty-five lateral hard and soft tissue landmarks were digitized, using the "on-screen" digitizing option, for each cephalogram and for each computer predicted posttreatment tracing. A customized analysis consisting of 24 linear and 4 angular measurements was used to analyze the differences between the actual posttreatment cephalometric landmark measurements and computer predicted landmark measurements. Statistically significant differences between the posttreatment cephalometric soft tissue profiles and the computer predicted soft tissue profiles were analyzed for the total sample, patients grouped according to: magnitude and direction of maxillary movements, adjunctive genioplasty procedure, V-Y closure of the LeFort I incision, and gender and age differences. The results indicated that for some of the soft tissue landmarks, differences were found between the posttreatment and the computer predicted profiles. Differences between the predicted and actual posttreatment soft tissue profiles may be attributed to the inaccuracy of Quick Ceph Image's default soft to hard tissue ratios when predicting the soft tissue response to combined maxillary and mandibular orthognathic surgical procedures.

Adolescent↗
PubMed1997

Combined rapid maxillary expansion and protraction facemask in the treatment of Class III malocclusions in growing children: a prospective long-term study.

A prospective study of 28 growing children (mean age of 8 years 3 months) with Class III malocclusions was consecutively treated using rapid maxillary expansion and maxillary protraction. All patients were treated from a negative overjet to a positive overjet and from a Class III dental malocclusion to a Class I dental relationship. For each patient, a lateral cephalogram was taken before treatment (T1), immediately posttreatment (T2), and after an observation period (T3) averaging 2 years 5 months. Using analysis of variance, the cephalograms were analyzed to determine skeletal and dental changes resulting from treatment. Long-term changes (2 years 5 month observation period) were also evaluated. Results showed that immediately posttreatment, the maxilla moved anteriorly a mean of 1.54 mm and Sella-Nasion-A point increased 0.87 degree. The maxillary teeth moved anteriorly 2.73 mm and proclined 5.23 degrees, while the mandible rotated in a downward and backward direction. Long-term, the anterior position of the maxilla was maintained, but some of the Class III correction was lost because of mandibular growth. Comparison of this study's results to Riolo's longitudinal Class I data showed that, overall, rapid palatal expansion and maxillary protraction produced a small orthopedic effect with a moderate dentoalveolar effect which together contributed to the correction of the Class III malocclusion.

Adolescent↗
PubMed1997

Discrepancies between centric occlusion and centric relation in orthodontically treated patients.

Condylar position between centric occlusion (CO) and centric relation (CR) was compared for 24 adolescent orthodontic patients at pretreatment, posttreatment, and during the retention phase of orthodontic treatment. Models were mounted using a face-bow transfer and CR interocclusal registrations. Differences in CO-CR were then measured at the condylar level in the x, y, and z dimensions. The data were analyzed statistically to determine the mean CO-CR differences in the sample as well as the magnitude and direction of the CO-CR differences from one time period to the next. Results showed that the mean three-dimensional distance between CO and CR tended to increase from pretreatment to the retention phase for the right and left sides, the left side showing a greater increase. Intraexaminer variability accounted for 20% to 25% of the total variability when all possible sources of variability were considered. Correlation with a second examiner in recording CR was in the range of .61 and .75 for the right and left sides, respectively. Interexaminer variability was found to be similar to the variability associated with the CO-CR discrepancies over time. Consequently, the differences in measurements obtained could be the result of changes in the CO-CR relationship, examiner variability, or a combination of both.

Adolescent↗
PubMed1997

A three-dimensional analysis of mandibular arch changes following curve of Spee leveling in nonextraction orthodontic treatment.

The present study was conducted to determine the effects of curve of Spee leveling on three-dimensional arch length and specific components of arch form. The mandibular pretreatment and posttreatment dental casts of 33 patients treated orthodontically without the extraction of teeth were digitized with a three-dimensional positioning transducer integrated with a graphics calculator. Statistical analysis was carried out with general linear models and the calculation of Pearson correlation coefficients of the relationships between the dependent variable of the curve of Spee leveling and the independent variables of arch length, arch depth, and three arch widths. The regression and correlation analyses essentially showed no relationship between the independent variables (arch length, arch depth, and the three arch widths) and the dependent variable (curve of Spee leveling). Although the three-dimensional arch length was increased after leveling of the curve of Spee in 24 of the 33 dental casts evaluated, the results from the statistical analyses indicated that this increased arch length was not necessarily the result of the curve of Spee leveling but may have been caused by other variables.

Computer Graphics↗
PubMed1996

Studies of temporomandibular joint sounds; Part 4. Phase relations of TMJ sounds and jaw movement.

A study was conducted to investigate the timing relationship of temporomandibular joint (TMJ) sounds during mandibular movement, as evaluated by the location of the condyle, in relation to the articular fossa using axiograph recording. TMJ sounds during jaw opening and closing occurred over a wide range: opening sounds were observed within a range of 41-100% of maximum opening, while closing sounds occurred within 1-80% of maximum opening. In calculating the peak frequency of the joint sounds, it was noted that there was no correlation between the timing of the sound and its peak frequency. This study revealed that the acoustic characteristics of TMJ sounds may be unaffected by the location of the condyle.

Auscultation↗
PubMed1994

Resorption patterns following intentional vital root transection in Macaca mulatta.

Previous studies have shown degeneration of nerve tissue as well as reorganization by periodontal tissue in dental pulp chambers following intentional vital root transection in Macaca mulatta. The supporting structures of the teeth, as well as the root itself, have not been fully studied following such surgery. The purpose of this study was to observe histopathologic changes in bone and root structure over a 1-year postoperative period. Three adult Macaca mulatta were evaluated for this study. Roots were transected within the apical one third and the areas were surgically closed. Following a postoperative soft diet for 7 days, the monkeys were allowed normal masticatory function. Maxillary and mandibular quadrants were removed following vascular perfusion of the animals at 1, 2, 3, 6, 24, and 52 weeks; quadrants were then demineralized, embedded, sectioned, and stained with Preece's trichrome. Resorption of cementum, dentin, and bone was independently evaluated on microslides for each tooth at consecutive intervals of approximately 70 microns. Resorption was rated as mild, moderate, or severe depending on the number of Howship's lacunae and the dimension of the resorptive area. Severe bone resorption was evident at 1 week, decreasing at 2 weeks, and then progressively decreasing up to 52 weeks. Most active inflammatory root resorption was noted on maxillary and mandibular premolars and molars on first-week specimens. Arrested resorptive areas were present in similar locations in second- and third-week specimens. New cementum was present along the cut surface on specimens from 2 to 52 weeks and within the pulp canal beginning at 2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Patterns of nerve regeneration in dental pulps of monkeys following surgical transection at 1 year.

Previous studies have reported revascularization and reorganization of dental pulp chambers with periodontal tissues of monkeys following complete surgical transection through a portion of the apical roots. This study observed 128 teeth in four adult monkeys. Following surgical transection, the tissues were acquired by perfusion fixation, serially sectioned, and stained for cellular detail with hematoxylin and eosin. Collagen tissues were stained with Preece's trichrome and neural tissues with Rowles' silver cyanate for controlled impregnation. At 1 and 2 weeks the coronal tissues showed tissue disruption, necrosis, and degenerating nerves. The 3- and 4-week tissues that had been completely transected showed replacement healing of the pulp tissue with periodontal ligament connective tissue, but no nerves were present. At 6 weeks, no nerves were present in the coronal chambers of those teeth with complete vital transection. The 24-, 36-, and 52-week pulp chambers with complete transection failed to show nerve fibers in their reorganized connective tissues.

Animals↗
PubMed1992

Temporomandibular joint sounds and condyle/disk relations on magnetic resonance images.

This study compared the condyle/disk relationships on magnetic resonance images (MRIs) in a group of subjects with completely silent temporomandibular joints (TMJ) when tested clinically with those in subjects with readily discernible TMJ sounds. The sounds were recorded with an accelerometer as the transducer. Selected degrees of jaw separation were electronically determined and recorded with interocclusal wafers for use with the imaging process. Of the "silent joints" 89% were found to have sounds when tested with the accelerometer. These "subclinical" sounds tended to be of shorter duration and occurred at a greater degree of vertical opening than the clinically discernable sounds. The MRIs of the group with clinically discernable sounds tended to show a change in the relationship between the head of the condyle and the intermediate zone of the disk, at the degree of jaw separation of the sound occurrence, whereas no condyle/disk change occurred in the group with "clinically silent joints." It is likely that all joints create sound during function. The different characteristics of the subclinical sounds versus the clinical sounds may indicate differing sound origins.

Adult↗
PubMed1990

Effects of etchant concentration and duration on the retention of orthodontic brackets: an in vivo study.

Etching of enamel before the bonding of orthodontic attachments is usually done with a solution of 37% H3PO4 for 60 seconds. The purpose of this study was to evaluate the effects of etchant concentration and duration on the clinical retention of bonded orthodontic attachments. Two randomly selected groups of orthodontic patients participated in the study. In both groups, teeth in contralateral quadrants, excluding the molar teeth, were bonded. In the first group, 158 teeth were etched with a solution of 37% H3PO4 for 60 seconds, and 155 teeth were etched with 37% H3PO4 for 15 seconds. In the second group, 196 teeth were etched with 37% H3PO4 and 196 teeth with 15% H3PO4, both for 60 seconds. Conventional edgewise mechanotherapy was used in both groups of patients. After 24 months of treatment, in the first group, 8 brackets were dislodged when etched with 37% H3PO4 for 60 seconds and 9 when etched with 37% H3PO4 for 15 seconds. In the second group, 6 brackets were dislodged when etched with 37% H3PO4 for 60 seconds and 13 were dislodged when etched with 15% H3PO4 for 60 seconds. Reducing the etching time of 37% H3PO4 from 60 seconds to 15 seconds or reducing the acid concentration from 37% to 15% H3PO4 applied for 60 seconds had no significantly different effect on the retention of bonded orthodontic attachments. The results suggest that the reduction of etchant concentration and the duration of etching in orthodontic bonding should be considered.

Acid Etching, Dental↗
PubMed1989

Effects of phosphoric acid concentration and etch duration on the shear bond strength of an orthodontic bonding resin to enamel. An in vitro study.

The purpose of this in vitro study was to determine the effects of phosphoric acid (H3PO4) concentration and duration of etching on the shear bond strength of an orthodontic bonding resin to enamel. Nine bonding procedures, each involving 18 extracted human maxillary permanent canines, were used. Ground enamel surfaces were etched with a 37% H3PO4 solution, a 15% H3PO4 gel, or a 5% H3PO4 solution for 60, 30, and 15 seconds, respectively. Cylinders of an orthodontic bonding resin, Concise, were prepared in a special device. The test specimens were disassembled 15 minutes after preparation and stored in distilled water at 37 degrees C for 24 hours. A shear load was applied to the bonded cylinders at a crosshead speed of 0.02 in.min-1 in an Instron testing machine, and the shear bond strengths were calculated and expressed in MN.m-2. A two-factor analysis of the data showed that the H3PO4 concentration had no significant effect on the shear bond strength, but the duration of etching affected shear bond strength significantly. The enamel aspects of the fractured test specimens were examined microscopically and the percent failure within the bonding resin at the bonding sites estimated. The correlation between shear bond strength and percentage failure within the bonding resin was not significant. The effects of the nine etching procedures on ground and unground enamel surfaces were studied by scanning electron microscopy. The etching procedures produced well-defined etching patterns on both ground and unground enamel surfaces.

Acid Etching, Dental↗