Abstract

The occlusal patterns and morphology of the dentition of the Navajo Indians were studied and compared to those of populations of known Mongoloid ancestry. Thirteen dento-anthropomorphic characteristics were studied from plaster casts obtained from fifty-four Navajo Indians from the Monument Valley area of Utah. The thirteen characteristics included were:

  1. Degree of shovel-shape of the maxillary centrals and laterals.
  2. Presence of a winged appearance in the maxillary centrals.
  3. Mesiodistal crown diameters of the maxillary centrals and laterals.
  4. Type of lingual tubercle on the maxillary centrals and laterals.
  5. Cusp pattern of mandibular molars.
  6. Cusp pattern of maxillary molars.
  7. Frequency of cusp of Carabelli.
  8. Degree of occlusal wear.
  9. Occurrence of mandibular and maxillary tori.
  10. Number of cusps on mandibular second premolars.
  11. Length and width of mandibular arch.
  12. Length, width, and palatal depth of maxillary arch.
  13. Classification of malocclusions.

The results of the analysis for each of the characteristics studied were compared with findings reported from similar studies on populations of known Mongoloid stock when available.

On the basis of the results obtained and the comparisons made, it is concluded that:

  1. The central and lateral incisors of the Navajo in this study exhibited a 100 per cent frequency of shovel-shaping, 95 per cent of which were in the more marked categories.
  2. A mesial torsion of the central incisors was found to occur in 42.2 percent of the dentitions examined.
  3. A mean difference of 1.29 mm. between the mesiodistal crown diameter of the centrals and laterals was recorded for the Navajo as compared to 2.03 mm. for Whites.
  4. The frequency of occurrence of a lingual tubercle was 34.2 percent and when present was most frequently Type B.
  5. The lower first molar is the most resistant to change in pattern, the second molar is less resistant, and the third molar is least resistant.
  6. The reduction of the fourth cusp is seen least in the maxillary first molar, more in the second molar, and most in the third molar.
  7. There was a 14.5 per cent frequency of occurrence of the cusp of Carabelli as compared to 49 per cent for American Whites.
  8. A relatively high degree of occlusal wear is present with the greater degrees more prevalent in older subjects.
  9. A frequency of 31.5 per cent was recorded for mandibular tori as compared to 6. 1 per cent in the American Whites.
  10. Maxillary tori were seen in only one subject.
  11. A frequency of 16.2 per cent was recorded for three cusped mandibular second premolars.
  12. The breadth of the mandibular and maxillary dental arches in the area of the first molars is greater than that recorded for Aleuts and American Whites of European origin.
  13. The length of the maxillary and mandibular dental arches is similar for Navajos and Whites of European origin.
  14. The Navajo presents a maxillary dental arch that is wider in the area of the first molars and has a greater palatal height than the maxillary dental arch of the Aleut.
  15. The most common malocclusion was the Class I type; the Class II type was the less common; and the Class III type was the least common in the subjects examined.
  16. The Navajo exhibits a psalidodont type of bite similar to that found in Whites.
  17. The Navajos in this study conform positively to the four criteria that have previously been established for the Mongol master pattern.

LLU Discipline

Orthodontics

Department

Dentistry

School

Graduate Studies

First Advisor

Thomas J. Zwemer

Second Advisor

Kenneth R. Lutz

Third Advisor

Gayle H. Nelson

Fourth Advisor

Lloyd Baum

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1964

Date (Title Page)

6-1964

Language

English

Library of Congress/MESH Subject Headings

Dental Occlusion; Indians, North American.

Type

Thesis

Page Count

xi; 119

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage 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.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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