published_or_final_version / Dentistry / Master / Master of Orthodontics

The lateral cephalometric radiograph (LCR) is an important tool in orthodontics to aid diagnosis, inform treatment planning and to evaluate treatment outcomes. Following identification of frequently used cephalometric analyses in the literature, the aims of this thesis were: (i) to establish cephalometric norm values for 12-year-old southern Chinese children for the modified Björk’s analysis, Jacobson’s Wits appraisal, Pancherz’s Sagittal Occlusal (SO) and Vertical Occlusal (VO) analyses (Paper I and II); (ii) to identify gender and racial/ethnic variations in cephalometric norm values (Paper I and II); (iii) to extrapolate from the cephalometric norm values of 12-year-old southern Chinese to produce norm values for 10, 11, 13 and 14-year-old - for these common aforementioned cephalometric analyses and McNamara’s analysis (Paper III); (iv) to investigate variations in the cephalometric characteristics of southern and northern Chinese children (Paper IV); and (v) to study the relationship between common cephalometric reference planes and the True Horizontal Plane (THP), and variations with respect to gender (Paper V). Extant LCRs from a community based sample of 200 male and 205 female 12-year-old southern Chinese in Hong Kong; 86 Caucasian children and 100 northern Chinese children, were traced and digitized twice employing the Computer Assisted Simulated for Orthognathic Surgery (CASSOS) program. Cephalometric norm values were created and extrapolated for 10 to 14-year-old. Gender and racial/ethnic variations were determined. In addition, the relationship between some common cephalometric reference planes (Sella Nasion Plane - SNP; Constructed Horizontal Plane - CHP; Frankfurt Horizontal Plane - FHP; Upper Occlusal Plane - UOP; Functional Occlusal Plane - FOP) and the THP was determined; and gender differences examined. Cephalometric norm values for modified Björk’s analysis, Jacobson’s Wits appraisal and Pancherz’s SO & VO analyses were produced for 12-year-old southern Chinese children. Variations in cephalometric norm values with respect to gender (P<0.05) and race/ethnicity (P<0.05) were observed. Extrapolated cephalometric norm values for modified Björk’s analysis, Jacobson’s Wits appraisal, Pancherz’s SO & VO analyses, and McNamara’s analysis were produced for 10 to 14-year-old. Variations in cephalometric norm values with respect to age (P<0.05), gender (P<0.05) and race/ethnicity (P<0.05) were observed. Furthermore, variations in cephalometric values between southern and northern Chinese children were evident (P<0.05), and between Caucasians and both Chinese groups (P<0.05). The mean inclination between THP and the conventional cephalometric planes differed significantly from zero: SNP/THP (P<0.05), UOP/THP (P<0.05), FOP/THP (P<0.05); and gender differences were apparent (P<0.05). In conclusion, norm values for frequently used cephalometric analyses were produced for 12-year-old southern Chinese, and extrapolated to produce norm values for 10 to 14-year-old. Age, gender and racial/ ethnic differences were apparent, supporting the need for age, gender and racial/ethnic specific norms. Common cephalometric reference planes differed to THP, and this warrants consideration in cephalometric analyses. / published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

Thesis (M. Orth.)--University of Hong Kong, 2005.

Thesis (M.S.)--Ohio State University. / Includes bibliographical references. Available online via OhioLINK's ETD Center.

Indiana University-Purdue University Indianapolis (IUPUI) / This investigation examined the prevalence, relative magnitude, and selected components of velar stretch in normal-speaking 8 and 10-year-old children. For twenty 8-year-old and twenty 10-year-old children, lateral cephalometric films were obtained under three conditions: (1) subject at rest, (2) subject sustaining the vowel /u/, and (3) subject sustaining the voiceless fricative /s/. The cephalometric films were traced on acetate paper and specific radiographic measurements were made to describe important facets of velar stretch in children. Data were obtained on the resting length of the soft palate, the antero-posterior depth of the pharynx, and the prevalence of velopharyngeal closure and/or the degree of velopharyngeal opening observed during selected speech utterances in normal-speaking 8 and 10-year-old children. Such information is expected to be useful to dentists, speech pathologists, and physicians who use lateral headplates to assess velopharyngeal adequacy. Velar stretch per se was not observed in all 40 normal-speaking children. During the production of /u/, 36 children (90%) exhibited velar stretch; for /s/, 32 children (80%) manifested stretch. Paired- comparison t-test results showed that the length of the soft palate measured during speech was significantly greater than its resting length in both 8 and 10-year-old children. Moreover, significantly more total velar stretch was found during the production of the vowel /u/ than during the production of the consonant /s/ in both 8 and 10-year-old children. Although there was a significant increase in the length of the entire soft palate during the functional activities of speech, no significant increase in the anterior portion of the soft palate was associated with speech. Analysis of variance techniques showed that 10-year-old children exhibited significantly greater velar stretch during both /u/ and /s/ utterances than did 8-year-old children. In addition, 10-year-old children exhibited significantly greater velar height and greater velar length characteristics during both /u/ and /s/ utterances than did 8-year-old. children. Correlation procedures were used to examine the relationships between velar stretch and other commonly employed cephalometric measures. These analyses indicated that although velar stretch was significantly correlated with a number of commonly employed cephalometric measures, the amount of velar stretch was not well predicted by any single cephalometric measure used in this research.

Indiana University-Purdue University Indianapolis (IUPUI)

Thesis (M.S.)--University of Michigan, 1966.

Thesis (M.S.)--University of Michigan, 1966.

Thesis (M.S.)--University of Michigan, 1958.