Biomedical subjects

A R Zaher

Publications and source records attributed to A R Zaher.

5 recordsLinked to original sources

PubMed1997

Treatment and posttreatment changes in patients with Class II, Division 1 malocclusion after extraction and nonextraction treatment.

The purpose of this study was to evaluate the treatment and posttreatment changes in the facial and dental parameters in two groups of patients with Class II, Division 1 malocclusions. In one group (n = 46), the patients were treated with a nonextraction approach, whereas in the second group (n = 45), the treatment included the extraction of four first premolars. The treatment groups were compared with matched untreated normals (n = 35) from the Iowa Growth Study. Lateral cephalograms and dental casts were evaluated at three stages: pretreatment, posttreatment, and approximately 2 years after treatment. Student's t tests were used to compare the extraction and nonextraction groups. Significance was predetermined at p < or = 0.05. The cephalometric findings indicate that before treatment, the subjects treated with four first premolar extractions had more protrusive upper and lower lips and a larger tooth size-arch length discrepancy. After treatment the upper and lower lips were more retrusive in the extraction groups, and more protrusive in the nonextraction groups. The extraction groups tended to have straighter faces and slightly more upright maxillary and mandibular incisors, whereas the nonextraction groups had the opposite tendencies. The average soft tissue and skeletal measurements for both groups were close to, but on opposite sides of, the corresponding averages derived from the Iowa normative standards. The findings from the dental arch measurements indicate that after treatment both the extraction and nonextraction groups experienced an increase in tooth size-arch length discrepancy and a reduction in arch length. In general, extractions did not significantly alter the direction of the overall posttreatment trends. Furthermore, the trends in the posttreatment changes were similar in male and female patients, as well as in the maxillary and mandibular arches. The current findings suggest that the extraction/nonextraction decision, if based on sound diagnostic criteria, does not have a systematic detrimental effect on the facial profile. But clinicians should be aware of the trends introduced by the two treatment modalities to avoid accentuating undesirable profile characteristics.

Adolescent↗

PubMed1995

Dentofacial and soft tissue changes in Class II, division 1 cases treated with and without extractions.

The purpose of this study was to compare the changes in subjects with Class II division 1 malocclusions treated with and without the extraction of four first premolars. Lateral cephalograms on 91 patients (44 extraction and 47 nonextraction) were evaluated at three stages: pretreatment, posttreatment, and approximately 2 years after treatment. The present findings indicate that before treatment, the upper and lower lips were more protrusive relative to the esthetic plane among the subjects treated with four first premolar extractions. After treatment the upper and lower lips were more retrusive in the extraction group, and more protrusive in the nonextraction groups. The extraction group tended to have straighter faces and slightly more upright maxillary and mandibular incisors, whereas the nonextraction group had the opposite tendencies. The average soft tissue and skeletal measurements for both groups were close to the corresponding averages derived from the Iowa normative standards. In general, differences between the groups after treatment were preserved into retention. The present findings indicate that the extraction or nonextraction decision, if based on sound diagnostic criteria, seem to have no deleterious effects on the facial profile.

Adolescent↗

PubMed1994

Effects of orthodontic treatment on the growth of individuals with Class II division 1 malocclusion.

The purpose of this study was to determine the effects of orthodontic treatment on the growth potential and dentofacial characteristics of individuals with Class II, division 1 malocclusion over a 5-year period. The changes were compared to matched, untreated normal individuals. Lateral cephalograms were available on 91 treated Class II, division 1 cases. Of these, 44 individuals (21 males and 23 females) were treated with first premolar extractions and 47 (20 males and 27 females) were treated nonextraction. The Class II groups were compared to 35 normal individuals (20 males and 15 females) matched for age and sex. Pretreatment, the Class II individuals had larger overjet, deeper overbite, larger ANB angle, more retrusive mandible and a convex soft tissue profile. In addition, the upper and lower lips in males, and the lower lip in females were significantly more protrusive in the subjects that were eventually treated with the extraction of four first premolars. At the end of the 5-year observation period, there was an overall "normalization" of the skeletal relationships of the treated Class II subjects in both the extraction and the nonextraction groups when compared to normals. Treatment had a differential impact on the dental relationships as well as on lip prominence as a result of the extraction decision. At the end of the observation period, both males and females in the extraction group had more retrusive maxillary and mandibular incisors as well as more retrusive lips than the corresponding normals. In the nonextraction groups, there was a tendency for both the incisors and the lips to be relatively more protrusive.

Adolescent↗

PubMed1994

Comparisons of the dental arch changes in patients with Class II, division 1 malocclusions: extraction vs nonextraction treatments.

Treatment and posttreatment changes in the dental arches of patients with Class II, division 1 malocclusions were evaluated. Half the patients (N = 46) were treated with a nonextraction approach; treatment for the other half (N = 45) included the extraction of four first premolars. The following parameters were measured in the maxillary and mandibular arches: arch width at the incisors, canines, second premolars and first permanent molars; anterior, posterior and total arch lengths; and total and anterior tooth size-arch length discrepancies. These parameters were measured pretreatment, immediately following orthodontic treatment and at least 2 years posttreatment. The findings indicate that the extraction of premolars significantly improves the discrepancy between the tooth size and arch length during treatment. Posttreatment both the extraction and nonextraction groups experienced an increase in tooth size-arch length discrepancies and a reduction in arch length. Extractions did not significantly alter the direction of the overall posttreatment trends for some parameters, e.g., intercanine width and tooth size-arch length discrepancies. On the other hand, the posttreatment trends for other parameters--such as intermolar width--were significantly different between the extraction and nonextraction groups. In general, the trends in the posttreatment changes were similar in males and females as well as in the maxillary and mandibular arches.

Bicuspid↗

PubMed1994

Posttreatment changes in different facial types.

The purpose of this study was to describe and compare the changes occurring during and after orthodontic treatment in three facial types: short, average and long. Sixty-six subjects with Class II, Division 1 malocclusion were evaluated. All cases were treated nonextraction, using a fixed edgewise appliance and extraoral forces. The lateral cephalogram and dental casts for each patient were measured at three different stages: pretreatment, immediately after appliance removal and at least two years posttreatment. There was a wide range of individual variation in posttreatment change for the various skeletal and dental parameters measured. With few exceptions, the three facial types did not show significant differences in posttreatment change. The relative protrusion of maxillary incisor tip (U1:A-Pog) tended to increase after treatment in the long face type while it tended to decrease in the short face type. Long face females, when compared with all other groups, showed greater posttreatment incremental increase in anterior face height as well as the greatest posttreatment decrease in maxillary arch length. Males expressed greater posttreatment incremental increases in the various linear measurements of face height than females. Differences in posttreatment change for the different facial types do not require special retention consideration.

Adolescent↗