the relationship between lip thickness and lip displacement in response to incisor movement

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The relationship between lip thickness and lip displacement in response to incisor movement H. Abar Department of Orthodontics, University of the Pacific, San Francisco, Calif Balance and harmony of the face rely on the morphologic relationships of the nose, lips, and chin, as well as the underlying skeletal components. Orthodontic treatment can alter the balance among these structures. Some studies have related the effect of orthodontic treatment on lip positions in response to incisor retraction. However, the nature of correc- tion between incisor retraction and lip adaptation is still controversial. This study was undertaken to investigate the influence of lip thickness on the relationship between dental and integumental tissue changes in orthodontically treated patients. Our sample was randomly selected from patients at the University of the Pacific from 1988 to 1992. All patients were treated with edgewise appliances. Cephalometric head- films of 30 late-adolescent and adult patients were digitized and analyzed for changes in the integumental profile with treatment. We found a moderately significant correlation between the osseous changes and soft-tissue changes of the 4 points measured: Point A to superior labial sulcus (r 0.64), maxillary incisors to upper lip (r 0.82), mandibular incisors to lower lip (r 0.73), and Point B to inferior labial sulcus (r 0.78). However, no significant correlation was observed between the lip thickness and the ratio of the perioral soft-tissue response to the hard-tissue movement. These results suggest that gross tooth movement may not have a proportional effect on the profile contour and that soft tissues may be self-supporting. 0889-5406/2002/$35.00 0 8/8/122492 doi:10.1067/mod.2002.122492 Orthodontic treatment outcome using the ABO grading system for dental casts H. Amer Department of Orthodontics, University of the Pacific, San Francisco, Calif This study compared the American Board of Orthodon- tics (ABO) grading system with clinicians’ subjective assess- ments, the peer assessment rating (PAR), and the handicap- ping labiolingual deviation index (HLD). Both intrarater and interrater agreements of the scoring of 36 cases were calcu- lated; there were 16 extraction and 20 nonextraction cases. For each of the 36 sets of final casts, an ABO score for tooth or contact was made by a group of orthodontists. Four orthodontists had been calibrated in its use, and a noncali- brated second-year resident graded the 36 final casts twice with at least 2 weeks between gradings. The PAR, the HLD, and the subjective assessment were taken from a previous study. There was a good correlation between the ABO score, the PAR rating, and the clinicians’ subjective score, but no correlation between the HLD and the clinicians’ subjective scores. A very good-to-excellent interrater reproducibility was found with the ABO grading system. Calibration helped to obtain more consistent intrarater reproducibility. Extraction cases scored slightly higher (worse) than nonextraction ones. 0889-5406/2002/$35.00 0 8/8/122493 doi:10.1067/mod.2002.122493 A quantitative analysis of the difference between right- and left- facing lateral cephalograms B. Caillouel Department of Orthodontics, University of the Pacific, San Francisco, Calif For initial diagnosis and evaluation of growth and treat- ment results, orthodontists use lateral cephalograms univer- sally. In the United States, lateral cephalograms are conven- tionally taken with the left side of the patient’s head closest to the film. In Europe, however, the convention is to place the right side of the patient’s head closest to the film. This difference in patient orientation is important because the resulting lateral cephalograms from the 2 techniques are not the same. Because of the divergent nature of x-rays, the structures of the craniofacial complex that are farthest from the film will be magnified more than those that are closer to the film. In this study, 4 dried skulls from the Spencer Atkinson Library of Applied Anatomy were used to deter- mine the differences in landmark identification between right- and left-facing lateral cephalograms, to determine the mag- nitude of the differences for conventional angular and linear measurements used in clinical analyses, to visually exhibit the differences with the technique of subtraction radiography, and to compare Denoptics digital images with conventional ana- log images. The results showed small differences in landmark identification and their resultant angular and linear measure- ments. Subtraction images of the bilateral cephalograms for each dried skull were produced to visually exhibit differences between the right-left pairs. The final part of the study, however, was abandoned because neither the Denoptics digital nor the analog image type was believed to be optimally exposed. 0889-5406/2002/$35.00 0 8/8/122494 doi:10.1067/mod.2002.122494 ARTICLE REVIEWS Amalgam—resurrection and redemption. Part 2: The medical mythology of anti-amalgam Michael J. Wahl Quintessence International 2001;32:696 –707 American Journal of Orthodontics and Dentofacial Orthopedics Volume 121, Number 3 Reviews and Abstracts 329

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The relationship between lip thicknessand lip displacement in response toincisor movementH. AbarDepartment of Orthodontics, University of the Pacific, SanFrancisco, Calif

Balance and harmony of the face rely on the morphologicrelationships of the nose, lips, and chin, as well as theunderlying skeletal components. Orthodontic treatment canalter the balance among these structures. Some studies haverelated the effect of orthodontic treatment on lip positions inresponse to incisor retraction. However, the nature of correc-tion between incisor retraction and lip adaptation is stillcontroversial. This study was undertaken to investigate theinfluence of lip thickness on the relationship between dentaland integumental tissue changes in orthodontically treatedpatients. Our sample was randomly selected from patients atthe University of the Pacific from 1988 to 1992. All patientswere treated with edgewise appliances. Cephalometric head-films of 30 late-adolescent and adult patients were digitizedand analyzed for changes in the integumental profile withtreatment. We found a moderately significant correlationbetween the osseous changes and soft-tissue changes of the 4points measured: Point A to superior labial sulcus (r � 0.64),maxillary incisors to upper lip (r � 0.82), mandibular incisorsto lower lip (r � 0.73), and Point B to inferior labial sulcus(r � 0.78). However, no significant correlation was observedbetween the lip thickness and the ratio of the perioralsoft-tissue response to the hard-tissue movement. Theseresults suggest that gross tooth movement may not have aproportional effect on the profile contour and that soft tissuesmay be self-supporting.

0889-5406/2002/$35.00 � 0 8/8/122492doi:10.1067/mod.2002.122492

Orthodontic treatment outcome usingthe ABO grading system for dental castsH. AmerDepartment of Orthodontics, University of the Pacific, SanFrancisco, Calif

This study compared the American Board of Orthodon-tics (ABO) grading system with clinicians’ subjective assess-ments, the peer assessment rating (PAR), and the handicap-ping labiolingual deviation index (HLD). Both intrarater andinterrater agreements of the scoring of 36 cases were calcu-lated; there were 16 extraction and 20 nonextraction cases.For each of the 36 sets of final casts, an ABO score for toothor contact was made by a group of orthodontists. Fourorthodontists had been calibrated in its use, and a noncali-brated second-year resident graded the 36 final casts twicewith at least 2 weeks between gradings. The PAR, the HLD,and the subjective assessment were taken from a previous

study. There was a good correlation between the ABO score,the PAR rating, and the clinicians’ subjective score, but nocorrelation between the HLD and the clinicians’ subjectivescores. A very good-to-excellent interrater reproducibilitywas found with the ABO grading system. Calibration helpedto obtain more consistent intrarater reproducibility. Extractioncases scored slightly higher (worse) than nonextraction ones.

0889-5406/2002/$35.00 � 0 8/8/122493doi:10.1067/mod.2002.122493

A quantitative analysis of thedifference between right- and left-facing lateral cephalogramsB. CaillouelDepartment of Orthodontics, University of the Pacific, SanFrancisco, Calif

For initial diagnosis and evaluation of growth and treat-ment results, orthodontists use lateral cephalograms univer-sally. In the United States, lateral cephalograms are conven-tionally taken with the left side of the patient’s head closest tothe film. In Europe, however, the convention is to place theright side of the patient’s head closest to the film. Thisdifference in patient orientation is important because theresulting lateral cephalograms from the 2 techniques are notthe same. Because of the divergent nature of x-rays, thestructures of the craniofacial complex that are farthest fromthe film will be magnified more than those that are closer tothe film. In this study, 4 dried skulls from the SpencerAtkinson Library of Applied Anatomy were used to deter-mine the differences in landmark identification between right-and left-facing lateral cephalograms, to determine the mag-nitude of the differences for conventional angular and linearmeasurements used in clinical analyses, to visually exhibit thedifferences with the technique of subtraction radiography, andto compare Denoptics digital images with conventional ana-log images. The results showed small differences in landmarkidentification and their resultant angular and linear measure-ments. Subtraction images of the bilateral cephalograms foreach dried skull were produced to visually exhibit differencesbetween the right-left pairs. The final part of the study,however, was abandoned because neither the Denoptics digitalnor the analog image type was believed to be optimally exposed.

0889-5406/2002/$35.00 � 0 8/8/122494doi:10.1067/mod.2002.122494

ARTICLE REVIEWS

Amalgam—resurrection andredemption. Part 2: The medicalmythology of anti-amalgamMichael J. WahlQuintessence International 2001;32:696–707

American Journal of Orthodontics and Dentofacial OrthopedicsVolume 121, Number 3

Reviews and Abstracts 329