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.

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.

Diagnosis and treatment of transverse maxillary deficiency.

Treatment of skeletally mature patients is often complicated by inadequately treated or undiagnosed transverse skeletal discrepancy. This report emphasizes diagnosis of transverse maxillo-mandibular discrepancy and describes recommendations for treatment. Proper treatment strategy must consider the type and magnitude of transverse deficiency, patient's growth status, dentofacial esthetics, stability factors, and periodontal tissue health. Indications for surgically assisted maxillary expansion are listed, and the recommended surgical technique to improve frontal dentofacial esthetics, provide better stability, and enhance long-term periodontal health is described. Specific modifications in surgical technique to help prevent postoperative complications are included. New recommendations for sequencing, timing, and correction of transverse deficiency are presented.