PubMed Health⌕ Search

Biomedical subjects

J Ghafari

Publications and source records attributed to J Ghafari.

At least 19 recordsLinked to original sources
PubMed2002

Comparison of CT scanograms and cephalometric radiographs in craniofacial imaging.

OBJECTIVE: To compare measurements from human skulls and their images from cephalometric radiographs (CR) and computed tomography (CT) scanograms, in order to gauge the potential clinical use of the latter. DESIGN: Based on specific inclusion criteria, including stable centric occlusion, 13 adult skulls were selected from a larger collection. The mandible was taped to the maxilla after securing the occlusion of teeth and condylar seating in the glenoid fossa. Lateral and posteroanterior cephalographs and CT 'scout views' were taken of each skull by standardized methods. Landmarks were identified on skulls and images. OUTCOME MEASURES: Linear measurements were made on all three records; angular measurements only on CR and CT images. Intraclass correlation coefficients (r) were calculated to assess similarity among records. Paired t-tests were used to compare differences between mean measurements. RESULTS: No statistically significant differences were noted between mean angular values on CR and CT views (P > 0.05). The highest correlations were observed for several vertical midline distances between CT and direct skull measures: 0.82 < r < 0.995-greatest for nasion-menton. For sagittal distances, the highest correlation was between the direct measure of condylion-pogonion and its CR image (r= 0.73). Correlations between CR and skull transverse measures were higher (0.46 < r < 0.80) than the corresponding skull vs. CT measures (0.06 < r < 0.38). CT and CR images are 2D slices and projections, respectively, of 3D structures. Vertical CT and skull measures correspond because the CT projection reflects a 1:1 ratio in the midsagittal plane; CT projected lateral images are smaller than the skull measures. The CR image reflects a distortion (approximately 8%) that brings Co-Pg closer to its anatomic distance, inadvertently contributing to better clinical planning, particularly in orthognathic surgery. The pattern of distortion of PA images was in opposite directions for CR and CT views. CONCLUSIONS: Cephalograms and CT scanograms are close in depicting angular relations of structures, but they differ in the accuracy of imaging linear measurements, because the location and size of an object within the imaged 3D structure varies with both records. Logistic and economic considerations favor the use of cephalographs.

Adult↗
PubMed2001

Effect of molar rotation on arch length.

The aim of this study was to evaluate the effect of maxillary first molar rotation on arch length in patients whose Class II, division 1 malocclusion was treated with a straight-pull headgear. The sample included 19 children who represent a subset of a population enrolled for 2 years in a prospective clinical trial of Class II treatment. The inner bow was adjusted at monthly visits and the average distalizing force was 14-16 oz per side. Measurements were made with digital calipers on casts obtained at baseline and at a time point averaging 16 months (SD 3 months) into treatment. Molar movement was related to a coordinate system referenced to the midpalatal raphae and the occlusal plane through a palatal plug that could be transferred to successive casts of the same patient. Distances from the cusp tips were measured to the reference system. The distal and lateral displacement, and the rotation of the molars over time were then computed. High correlations were observed between molar rotation and tooth displacement (that is the net differential movement between the mesiobuccal - MB - and mesiopalatal - MP - cusps): r=0.9, p=0.0001 (left side); r=0.8, p=0.0001 (right side). The average rotation of the molar was 15.4 degrees (SE+/-3.80) on the left side and 10.8 degrees (SE+/-2.20) on the right side. The average differential displacements between the MB and MP cusps were 1.04 mm (SE+/-0.29) (left) and 0.73 mm (SE+/-0.23) (right). The differences between the two sides were not statistically significant. The molar rotation did not correlate with any of the following parameters: initial tooth position; initial distance between the MB and MP cusps as a correlate of molar anatomy; transverse (mostly buccal) movement of the MB and MP cusps; distal movement of the tooth, as measured by the total displacement of the MB and MP cusps. This study qualifies the relationship between molar rotation and increase in arch length. The mean total distal movement of the molar was larger (nearly 3 mm) than the average contribution of molar rotation to space gain (about 1 mm), suggesting that the distal movement of the tooth was a combination of rotation and translation (or tipping). The contribution of the molar rotation is more significant with a smaller total displacement of the tooth.

Journal Article↗
PubMed2001

New posteroanterior cephalometric norms: a comparison with craniofacial measures of children treated with palatal expansion.

The aim of the study was to evaluate posteroanterior (PA) cephalometric characteristics in a normal longitudinal database and compare these measurements with corresponding measures in a group of patients treated with rapid maxillary expansion. Posteroanterior cephalographs of 16 girls and 14 boys from the Bolton-Brush growth study, taken at ages 10 and 18 years, were used to track growth in children with normal occlusion. Pretreatment PA cephalograms of 24 patients who had palatal distraction around age 10 were compared with the 10-year-old normal patients. Digitized landmarks included right and left jugale (J, at intersection of maxillary tuberosity and zygomatic buttress) and antegonion (AG, at notch of antegonial protuberance). Mandibular width (AG-AG) was similar in boys and girls at age 10 but not 18, when the difference between gender groups was statistically significant (P < .05). Maxillary width (J-J) was greater in boys than girls at both ages. The increase in AG-AG (5.5 mm, boys; 3.9 mm, girls) was more than twice that of J-J (2.4 mm, boys; 1.2 mm, girls). Arch width (at first molar) was nearly stable with age, indicating compensatory occlusal adaptation to differential changes between maxillary and mandibular widths. At age 18, the distance between the centers of the orbits, a surrogate measure of cranial width, was almost equal to J-J in girls and significantly correlated with AG-AG in boys (r = .71, P < .002) and girls (r = .77, P < .0001). The majority of treated children had both skeletal and dentoalveolar widths narrower than control values. Linear regressions between J-J and AG-AG revealed almost parallel slopes for control and treated groups in both genders, but the treated group was at a lower level, which is consistent with smaller maxillary widths.

Adolescent↗
PubMed2001

Magnetic resonance spectroscopy of the masseter muscle in different facial morphological patterns.

The aims of this study were (1) to develop a reliable noninvasive method to evaluate the masseter muscle metabolism, by using (31)P-magnetic resonance spectroscopy, and (2) to evaluate the metabolic profile of the masseter muscle in subjects with various facial patterns. The maxillary-mandibular relationship, which varied from hypodivergent to hyperdivergent, was measured on lateral cephalograms of 20 adults, 22 to 35 years of age. (31)P-spectra were acquired from the masseter muscle at rest with a custom-made, single-turn, double-tuned, 3 x 5-cm oblong surface coil. The inorganic phosphate to phosphocreatine (Pi/PCr) ratios were measured and compared in relation to vertical and sagittal cephalometric measurements. A statistically significant (R(2) = 0.65, r = 0.81, P = .001) relationship was found between Pi/PCr ratio and the palatal-to-mandibular plane angle. As the maxillary-to-mandibular divergence increased, the Pi/PCr ratio decreased. This correlation suggests that muscles with a higher Pi/PCr ratio have a higher resting metabolic activity than those with a lower Pi/PCr ratio. Consequently, these muscles may keep bone under more tension and influence its growth in a more horizontal direction. Another possible explanation of the results is that the fiber type composition of the masseter muscle varies with facial morphology.

Adult↗
PubMed2001

Endoscopic removal of an ectopic third molar obstructing the osteomeatal complex.

We report a rare case of an ectopic third molar at the level of the osteomeatal complex. A 21-year-old man came to us with a left-sided nasal obstruction of 2 years' duration. Computed tomography of the paranasal sinuses revealed that an aberrant tooth was obstructing the osteomeatal complex and bulging into the ethmoid infundibulum. Opacity of the entire left maxillary sinus indicated the presence of an associated cystic formation. A transnasal endoscopic sinus technique was employed to create a large middle meatal antrostomy and to remove the tooth as well as the cystic contents and cyst wall. Pathologic analysis revealed that the cyst was dentigerous. After recovery from surgery, the patient resumed nasal breathing. The endoscopic surgical approach used in this case caused less morbidity than do the more common methods (e.g., the Caldwell-Luc procedure) of removing ectopic teeth from the sinus.

Adult↗
PubMed2000

Seeking academia.

Explore the source record for details and available documents.

Journal Article↗
PubMed2000

Effect of landmark identification on cephalometric measurements: guidelines for cephalometric analyses.

Identification of craniofacial landmarks, particularly condylar anatomy, on the lateral cephalometric radiograph is erratic. The accuracy of recognition is critical for proper diagnosis of malocclusion and for assessing growth and orthodontic treatment. The aim of this study was to evaluate the identification of condylion and other cephalometric landmarks commonly used, or thought to be easily identifiable. A lateral cephalograph was taken on each of 34 adult subjects. Five examiners, three orthodontists, a dental radiologist and a second-year orthodontic resident rated the condyle, along with sella (S), nasion (Na), point A (A), infradentale (I), pogonion (Pog) and menton (Me) as identifiable, non-identifiable and interpreted. In addition, distances between several of these landmarks were measured. The left condyle, subject to less magnification than the right condyle because it is closer to the film, was more identifiable than the right condyle, which had the highest rating as non-identifiable. Among other landmarks, nasion and point A were the least identifiable, Pog and Me the most. Correlation coefficients for measurements between identifiable landmarks (I-Me) were greater than coefficients for distances involving less identifiable landmarks (S-A). Interestingly, linear measurements were less variable than the identification of corresponding landmarks. These findings corroborate the previous conclusions that clearly identifiable (and the least amount of interpreted) landmarks should be used for proper evaluation of dentofacial relationships. They also suggest, on average, precision in landmark identification is more critical for research purposes than in routine clinical cephalomteric measurements, which serve only as a guide to diagnosis.

Journal Article↗
PubMed1999

Evaluation of differential growth and orthodontic treatment outcome by regional cephalometric superpositions.

Cephalometric superimposition on cranial base is the accepted method for evaluating mandibular displacement during orthodontic treatment and/or growth. However, assessing mandibular position relative to the maxillary base may yield different information. The aim of this study was to evaluate the effects of regional superpositions (cranial versus maxillary) on interpreting mandibular displacement. Both methods were applied to pre- and posttreatment cephalograms of 22 growing children (12 female, 10 male) treated for Class II Division 1 malocclusion. Differences in linear and angular measurements of three mandibular landmarks (pogonion, gnathion, menton) between cranial and maxillary superpositions were statistically significant (p = 0.0001). Vertical displacement of these landmarks contributed significantly to the differences (p = 0.0001). The contribution of horizontal displacement was not statistically significant. The results support the proposition that, in growing children, posttreatment displacement of mandibular skeletal and dental components should be assessed by both maxillary and cranial base superimpositions. The maxilla is subject to rotational and translational changes during growth that may affect the position of the mandible relative to the maxilla in a way inconsistent with the mandibular displacement perceived upon cranial superposition. Since occlusion is directly associated with the positions of the maxillary and mandibular basal bones, the positions of these bones relative to each other is critical in assessing occlusal changes in individual patients.

Adolescent↗
PubMed1998

Headgear versus function regulator in the early treatment of Class II, division 1 malocclusion: a randomized clinical trial.

A prospective randomized clinical trial was conducted to evaluate the early treatment of Class II, Division 1 malocclusion in prepubertal children. Facial and occlusal changes after treatment with either a headgear or a Fränkel function regulator are reported. Molar and canine relationships, overjet, intermolar and intercanine distances were measured from casts taken every 2 months, and mounted on a SAM II articulator. Cephalometric radiographs were taken annually. The results indicate that both the headgear and function regulator were effective in correcting the malocclusion. A common mode of action of these appliances is the possibility to generate differential growth between the jaws. The extent and nature of this effect, as well as other skeletal and occlusal responses differ. Treatment in late childhood was as effective as that in midchildhood. This finding suggests that timing of treatment in developing malocclusions may be optimal in the late mixed dentition, thus avoiding a retention phase before a later stage of orthodontic treatment with fixed appliances. However, a number of conditions may dictate an earlier intervention in the individual patient.

Adolescent↗
PubMed1998

Comparison of surface-treated and untreated orthodontic bands: evaluation of shear force and surface roughness.

In an attempt to increase retention of orthodontic bands, orthodontic companies market bands with surfaces prepared to increase roughness. A comparison of six groups of bands, including two with untreated surfaces, revealed a wide range of variation in shear forces. Three classes of retention may be differentiated on the basis of non-statistically significantly different mean shear forces in each category: high (Unitek, treated), moderate (Unitek, untreated; A Co., treated; GAC, treated), and low (A Co., untreated; Dentaurum, treated). Surface roughness, as evaluated through atomic force microscopy, correlated moderately with shear force (r = 0.61; p < 0.05). This method is examined and compared with the qualitative profiles of the orthodontic band surfaces provided by optical micrography.

Analysis of Variance↗
PubMed1998

Misinterpreting growth and treatment outcome from serial cephalographs.

This communication addresses the issue of interpretation of serial cephalometric records. Angular measurements provide information that combines the vertical and sagittal components of a landmark's displacement. For example, a decrease in the SNA angle following orthodontic treatment with a headgear demonstrates maxillary retraction relative to nasion, an important assessment to depict a change closely related to the facial profile. Upon superimposition on the anterior cranial base, however, the vertical movement of point A may be the prevalent displacement, which would still account for the decrease in the SNA angle. The superposition allows the evaluation of the displacement in its vertical and sagittal components separately, relative to a structure that is relatively more stable than nasion. The superimposition enhanced the precision of the information regarding the actual displacement of the jaw. A patient's cephalometric records are presented, further demonstrating that the interpretation of changes during growth and treatment should be based not only on angular measurements, but also on regional superpositions. The frames of reference of both procedures are needed to fully understand the facial changes.

Cephalometry↗
PubMed1998

Early treatment of Class II, division 1 malocclusion--comparison of alternative treatment modalities.

The purpose of this paper was to compare the findings from three randomized clinical trials that investigated alternative treatments of Class II, division 1 malocclusion in young children. The trials were conducted at the University of North Carolina, the University of Florida, and the University of Pennsylvania. The appliances investigated in each center were a functional appliance versus a headgear. Variations in the specific aims and the working hypotheses were noted. The types of appliances, length of treatment, and methods of evaluation were also different. A general comparison of selected clinically relevant findings reveals similarities and differences in conclusions, but underlines the importance of assessing each study on the basis of its original hypothesis. The separate and combined contribution of these studies to the state of knowledge and research is discussed.

Child↗
PubMed1998

Timing the early treatment of Class II, division 1 malocclusion--clinical and research considerations.

The aim of this study was to evaluate the correlation between timing of emergence of the permanent teeth and sagittal occlusal changes in children enrolled in a prospective clinical trial of Class II, division 1 treatment. The children, ages 7.2-13.3 years, met strict inclusion criteria and were assigned at random to treatment with either a headgear or a Fränkel functional appliance. Relationships between maxillary and mandibular first molars and canines, as well as overjet, were measured with digital calipers on casts made every 2 months and mounted on a SAM II articulator. The emergence of a permanent tooth was scored on a scale from 1 to 3, depending on the eruptive level of the tooth from cutting through the gingiva (1) to reaching the occlusal table (3). Specifically, emergence of the second premolars (PM2) and permanent second molars (M2), the most adjacent teeth to the first molars, was evaluated as it interacted with the development of the sagittal occlusion. Treatment of the distocclusion was as effective in late childhood as in mid-childhood. Within each appliance group, the emergence of PM2 and M2 did not affect the amount of progress toward Class I significantly (p > 0.05), indicating that improvement from distocclusion to neutrocclusion with each appliance is not influenced by the timing of emergence of these teeth. Although these findings support a one-phase treatment starting in the late mixed dentition, earlier intervention in mid-childhood may be required in the presence of several developmental conditions, or when the dental and skeletal development deviate significantly in the individual patient.

Adolescent↗
PubMed1997

Transverse development of the jaws: norms for the posteroanterior cephalometric analysis.

Norms available for the posteroanterior (PA) cephalometric analysis yield different information. The material used to generate these standards is not clearly defined. The purpose of this study was to use data from the Bolton-Brush Growth Study to generate new norms for the PA analysis. The Bolton material is recognized as a controlled longitudinal record of growing children. The assumption that growth in the transverse dimension is the first to be completed is challenged by finding that increments in maxillary and mandibular width vary, like sagittal and vertical growth, according to gender and chronologic age.

Adolescent↗
PubMed1996

Identification of condylar anatomy affects the evaluation of mandibular growth: guidelines for accurate reporting and research.

Mandibular length is measured on cephalographs to depict changes during growth and after orthodontic treatment, and is often defined between condylion (Co, most posterior superior point on the condylar outline) and pogonion (Pog, most anterior point on the chin). The aim of this study was to assess the accuracy of identifying condylar anatomy, thus the validity of using Co-Pog to evaluate mandibular growth. The sample included 34 children from a prospective study on the early treatment of distoclusions. Two lateral head films were taken of each child, the first with the mouth closed (MC), the second with the mouth open (MO). Three examiners, two orthodontists (U.H. and K.H.) and a dental radiologist (R.B.), rated the condyle as identifiable, nonidentifiable, and interpreted. The rating was applied to the left (L) and right (R) condyles, or to only one outline (O) when the R and L structures appeared superimposed and were not distinguished separately. Besides Co-Pog, the orthodontists traced sella-nasion (SN) and incisor tip-menton (I-Me) to evaluate variability in measurements that do not include Co. One operator (J.G.) measured all distances. Agreement among the three examiners was best in rating the MO radiographs (50%): 4.1% identifiable, 5.9% nonidentifiable or interpreted; in the MC films, they agreed in 32.3% of the cases, but only one of the ratings was identifiable (2.9%). The highest agreement was in identifying the left condyle on the MO film (35.3%). Intraclass correlation coefficients for CO-Pog ranged from r = 0.73 (L side) to r = 0.92 (O) for one orthodontist, and for the other from r = 0.76 (O) to r = 0.85 (L). Both orthodontists had high correlations for SN and I-Me between MC and MO (0.94 < r < 0.98). The variability between examiners in recognizing condylar anatomy, particularly on radiographs taken with the mouth closed, suggests that the identification of condylar anatomy must be rated in studies of mandibular growth. Researchers measuring mandibular length in investigations of mandibular growth after orthodontic therapy should differentiate between cases where the condyle is readily identified, and those where condylar anatomy is interpreted.

Cephalometry↗
PubMed1995

Effect of film-object distance on posteroanterior cephalometric measurements: suggestions for standardized cephalometric methods.

Posteroanterior (PA) cephalographs are used for diagnosis of transverse skeletal and dentoalveolar relationships. Unlike lateral head films, the variability of the PA radiograph has not been assessed. The purpose of this study was to evaluate the effect of film-object distance (film-ear rod, or film-porionic axis distance: FPD) and head angulation on transverse measurements from PA cephalographs. Seventeen skulls were selected from a total of 45 on the basis of strict criteria, including a stable reproducible centric occlusion. Radiographs were taken of each skull at the FPD of 11, 12, 13, and 14 cm. At the FPD of 11 and 14 cm, additional radiographs were taken at the angulations of +5 degrees and -5 degrees from the Frankfort horizontal (FH). Distances between the following landmarks were measured on the radiographs with digital calipers accurate to 0.01 mm: J (on the lateral contour of the maxilla), Ag (at the antegonial notch), Go (Gonion), Mb (buccal surface of mandibular first molar), IR (inner ramal point at the intersection of mandibular ramus and body). No clinically significant difference existed between measurements at the different FPDs evaluated. For this reason, and because the majority of PA films taken of 59 human subjects were within a FPD range below and including 13 cm, regression analyses were computed only at FPD = 13 cm. Correlation coefficients r between the distance AG-AG and distances J-J, IR-IR, and Mb-Mb were 0.71, 0.75, and 0.68, respectively. Transverse measurements were not significantly affected by a head angulation within 10 degrees (FH -5 degrees to +5 degrees).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Changes of arch width in the early treatment of Class II, division 1 malocclusions.

Changes in arch width during the early correction of Class II, Division 1 malocclusions with either the Fränkel functional appliance or headgear are compared in an ongoing prospective randomized clinical trial. The data were collected from 43 children, ages 7.5 to 12.85 years, who met strict dental and cephalometric criteria for inclusion in the study. They were assigned at random to treatment with either a headgear (n = 21) or a Fränkel appliance (n = 22). Occlusal measurements included the maxillary and mandibular intermolar distances (buccal and palatal/lingual) and intercanine distances. Measurements (millimeters) were performed on casts taken every 2 months, with digital calipers accurate to 0.01 mm. Four months after the initiation of treatment, the mean maxillary intermolar distance was larger in the Fränkel group (palatal: 1.58, SE: 0.22; buccal: 1.58, SE: 0.20) than the headgear group (palatal: -0.39, SE: 0.21; buccal: 0.26, SE: 0.23), and the difference was statistically significant (palatal: p < 0.0001 and buccal: p = 0.0001). The mean maxillary intercanine distance increased more with the headgear (1.62, SE: 0.19) than the Fränkel appliance (0.62, SE: 0.23) p = 0.003. As treatment progressed, the average intermolar distance in the headgear group increased, but was still higher in the Fränkel group by more than 1 mm. The intercanine distance remained larger in the headgear group. The mandibular intermolar and intercanine distances were higher after Fränkel therapy than with headgear.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗