Aim: The purpose of this study was to determine the prevalence of orthodontic extraction cases and the rationale for the decision-making. Materials & Methods: The records of consecutive patients who had completed orthodontic treatment at Graduate Orthodontic Clinic, Loma Linda University School of Dentistry, between January 2010 and December 2014 were reviewed for prevalence of orthodontic extractions. Cone beam computed tomograms (CBCTs) of patients, that had extraction(s) prescribed as part of orthodontic treatment, were analyzed dentally and skeletally. Patients were then categorized according to the degree of crowding in each dental arch. A one-way ANOVA (Kruskal-Wallis) test and Mann Whitney U with Bonferroni adjustments for post-hoc pair-wise comparisons were used for statistical analysis at α = 0.05. Results: There were 211 orthodontic extraction cases from 889 completed cases (23.7%). However, only 144 patients had sufficient records for further analysis in this study. Premolar extraction was prescribed in 134 patients (93.0%). Evaluation of each parameter based on degree of crowding revealed statistically significant differences in mandibular incisor to mandibular plane angle (L1-MP), interincisal angle, and maxillary incisor to Nasion-A point distance (U1-NA) [p < 0.05]. Furthermore, regardless of the degree of crowding, greater than 5 mm mandibular incisor to Nasion-B point distance (L1-NB) was observed in the majority of the cases (73.6%). Conclusions: Besides the degree of crowding, interincisal angle, L1-MP, U1-NA and L1-NB seem to be the determining factors in planning for orthodontic extraction cases.
","abstract_html":"<p><strong>Aim</strong>: The purpose of this study was to determine the prevalence of orthodontic extraction cases and the rationale for the decision-making. <strong>Materials & Methods</strong>: The records of consecutive patients who had completed orthodontic treatment at Graduate Orthodontic Clinic, Loma Linda University School of Dentistry, between January 2010 and December 2014 were reviewed for prevalence of orthodontic extractions. Cone beam computed tomograms (CBCTs) of patients, that had extraction(s) prescribed as part of orthodontic treatment, were analyzed dentally and skeletally. Patients were then categorized according to the degree of crowding in each dental arch. A one-way ANOVA (Kruskal-Wallis) test and Mann Whitney U with Bonferroni adjustments for post-hoc pair-wise comparisons were used for statistical analysis at α = 0.05. <strong>Results: </strong>There were 211 orthodontic extraction cases from 889 completed cases (23.7%). However, only 144 patients had sufficient records for further analysis in this study. Premolar extraction was prescribed in 134 patients (93.0%). Evaluation of each parameter based on degree of crowding revealed statistically significant differences in mandibular incisor to mandibular plane angle (L1-MP), interincisal angle, and maxillary incisor to Nasion-A point distance (U1-NA) [p < 0.05]. Furthermore, regardless of the degree of crowding, greater than 5 mm mandibular incisor to Nasion-B point distance (L1-NB) was observed in the majority of the cases (73.6%). <strong>Conclusions: </strong>Besides the degree of crowding, interincisal angle, L1-MP, U1-NA and L1-NB seem to be the determining factors in planning for orthodontic extraction cases.</p>","abstract_has_math":false,"creators":["Tran, Teresa T."],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Thesis","degree_discipline":"Orthodontics and Dentofacial Orthopedics","degree_department":null,"school":null,"contributors":["Rungcharassaeng, Kitichai","Caruso, Joseph M.","Olson, Gregory W."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-01T07:00:00Z","date_published":"2015-09-01T07:00:00Z","updated_at":"2026-07-24T02:52:38Z","subjects":["Dentistry","Medicine and Health Sciences","Orthodontics and Orthodontology","Tooth Extraction -- Statistics & numerical data; Orthodontics - Corrective; Cone-beam Computed Tomography;","Orthodontic extraction; Dentists - Decision Making; Mandibular incisor to mandibular plane angle; Interincisal angle; Dental crowding"],"languages":["English"],"rights":["This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarsrepository.llu.edu/etd/327","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Rungcharassaeng, Kitichai","Caruso, Joseph M.","Olson, Gregory W."]},{"key":"dc:creator","label":"Author","values":["Tran, Teresa T."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_discipline","label":"Discipline","values":["Orthodontics and Dentofacial Orthopedics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Dentistry","Medicine and Health Sciences","Orthodontics and Orthodontology","Tooth Extraction -- Statistics & numerical data; Orthodontics - Corrective; Cone-beam Computed Tomography;","Orthodontic extraction; Dentists - Decision Making; Mandibular incisor to mandibular plane angle; Interincisal angle; Dental crowding"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:rights","label":"Dc Rights","values":["This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarsrepository.llu.edu/etd/327"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Aim: The purpose of this study was to determine the prevalence of orthodontic extraction cases and the rationale for the decision-making. Materials & Methods: The records of consecutive patients who had completed orthodontic treatment at Graduate Orthodontic Clinic, Loma Linda University School of Dentistry, between January 2010 and December 2014 were reviewed for prevalence of orthodontic extractions. Cone beam computed tomograms (CBCTs) of patients, that had extraction(s) prescribed as part of orthodontic treatment, were analyzed dentally and skeletally. Patients were then categorized according to the degree of crowding in each dental arch. A one-way ANOVA (Kruskal-Wallis) test and Mann Whitney U with Bonferroni adjustments for post-hoc pair-wise comparisons were used for statistical analysis at α = 0.05. Results: There were 211 orthodontic extraction cases from 889 completed cases (23.7%). However, only 144 patients had sufficient records for further analysis in this study. Premolar extraction was prescribed in 134 patients (93.0%). Evaluation of each parameter based on degree of crowding revealed statistically significant differences in mandibular incisor to mandibular plane angle (L1-MP), interincisal angle, and maxillary incisor to Nasion-A point distance (U1-NA) [p < 0.05]. Furthermore, regardless of the degree of crowding, greater than 5 mm mandibular incisor to Nasion-B point distance (L1-NB) was observed in the majority of the cases (73.6%). Conclusions: Besides the degree of crowding, interincisal angle, L1-MP, U1-NA and L1-NB seem to be the determining factors in planning for orthodontic extraction cases.
"]},{"key":"dc:title","label":"Title","values":["Prevalence and Rationale of Orthodontic Extractions at Loma Linda University"]}]}],"canonical_facts":{"dc:contributor":["Rungcharassaeng, Kitichai","Caruso, Joseph M.","Olson, Gregory W."],"dc:creator":["Tran, Teresa T."],"dc:description.abstract":["Aim: The purpose of this study was to determine the prevalence of orthodontic extraction cases and the rationale for the decision-making. Materials & Methods: The records of consecutive patients who had completed orthodontic treatment at Graduate Orthodontic Clinic, Loma Linda University School of Dentistry, between January 2010 and December 2014 were reviewed for prevalence of orthodontic extractions. Cone beam computed tomograms (CBCTs) of patients, that had extraction(s) prescribed as part of orthodontic treatment, were analyzed dentally and skeletally. Patients were then categorized according to the degree of crowding in each dental arch. A one-way ANOVA (Kruskal-Wallis) test and Mann Whitney U with Bonferroni adjustments for post-hoc pair-wise comparisons were used for statistical analysis at α = 0.05. Results: There were 211 orthodontic extraction cases from 889 completed cases (23.7%). However, only 144 patients had sufficient records for further analysis in this study. Premolar extraction was prescribed in 134 patients (93.0%). Evaluation of each parameter based on degree of crowding revealed statistically significant differences in mandibular incisor to mandibular plane angle (L1-MP), interincisal angle, and maxillary incisor to Nasion-A point distance (U1-NA) [p < 0.05]. Furthermore, regardless of the degree of crowding, greater than 5 mm mandibular incisor to Nasion-B point distance (L1-NB) was observed in the majority of the cases (73.6%). Conclusions: Besides the degree of crowding, interincisal angle, L1-MP, U1-NA and L1-NB seem to be the determining factors in planning for orthodontic extraction cases.
"],"dc:identifier":["https://scholarsrepository.llu.edu/etd/327"],"dc:language":["English"],"dc:rights":["This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights."],"dc:subject":["Dentistry","Medicine and Health Sciences","Orthodontics and Orthodontology","Tooth Extraction -- Statistics & numerical data; Orthodontics - Corrective; Cone-beam Computed Tomography;","Orthodontic extraction; Dentists - Decision Making; Mandibular incisor to mandibular plane angle; Interincisal angle; Dental crowding"],"dc:title":["Prevalence and Rationale of Orthodontic Extractions at Loma Linda University"],"thesis:degree_discipline":["Orthodontics and Dentofacial Orthopedics"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T02:52:38Z"}