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Biomedical subjects

C B Preston

Publications and source records attributed to C B Preston.

At least 37 records · Page 2Linked to original sources
PubMed1984

Oral health status of the Lengua Indians of Paraguay.

The dental and oral health status of 202 Lengua Indians of Paraguay was determined using DMT, Russell's PI and the Greene & Vermillion OHIS. Caries experience in young Lenguas was shown to be positively associated with exposure to Western culture. Mean DMT increased from 8.36 for 15-19 yr-olds to 9.44 in 20-24 yr-olds. For the 25-29 yr age group the DMT was 9.10 whilst 30-34 yr-olds had a mean DMT of 8.67. The mean DMT of 9.64 for 35-40 yr-olds increased to 9.84 for the over 40 age group. Oral hygiene and periodontal status were found to be similar to those reported in other Chaco Indian groups.

Adolescent↗
PubMed1983

Hemifacial microsomia. A case report.

A case of hemifacial microsomia is presented. The mandible, temporomandibular joint, zygomatic arch and temporal region were reconstructed by means of skull bone grafts when the patient was 6 years old, a relatively early age. This corrective surgery has effectively restored normal mandibular function, and in so doing may encourage more acceptable development of the affected facial structures.

Bone Transplantation↗
PubMed1982

Postural response of the head to bite opening in adult males.

The postural position of the head is a resultant of muscular interactions and reactions, influenced by gravity and functional demands. In order to investigate possible postural adaptation of the head to an altered functional status, a standard degree of jaw opening was produced by mechanical means in the mouths of thirty young males. There was an extension of the head associated with the jaw separation. In the majority of cases, a recovery to approximately the original posture resulted within 1 hour after removal of the bite-opening device.

Adaptation, Physiological↗
PubMed1981

The dentition of the Lengua indians of Paraguay.

The crown morphology of 202 dental casts from living Lengua Indians is described and compared with other Amerind, Melanesian, and Caucasoid samples. The Lengua dentition shows a high Mongoloid component with little effects of possible European admixture, thus supporting the theory that despite early Franciscan and Jesuit attempts at missionization, much of the Paraguayan Chaco has remained genetically and culturally relatively intact well into the present century. A finding of note was the apparent sexual dimorphism of the Carabelli cusp, which questions earlier assumptions that no correction for sex need be made in population studies when dealing with this trait. Since mandibular canines show proportionately less wear in the canine distal accessory ridge area than maxillary canines, the value of the incidence of this trait in population and microevolutionary studies is questioned.

Adult↗
PubMed1981

Resistance to nasal airflow related to changes in head posture.

The relationship] between mode of respiration, cranial posture, and craniofacial morphology has been the subject of many articles in recent years. Some authors postulate that mouth breathers extend their heads backward in an effort to increase airway patency. The purpose of the present study was to determine whether artificially induced extended head posture decreases the resistance to nasal airflow. The experimental sample comprised fifteen male students with normal vertical facial proportions and no histories of chronic mouth breathing. In the sample, head posture was assessed by measuring the craniovertical angle by means of an angle finder. Nasal resistance units were calculated from the parameters of nasal airflow and differential pressure across the nasal airway during the complete respiratory cycle using an equation analogous to Ohm's law. Readings were obtained in both the normal and 10-degree extended head posture position, and the results were compared. No association could be found between an extended head posture position and a decreased resistance to nasal airflow.

Adult↗
PubMed1980

Maxillary canine retraction, periodontal surgery, and relapse.

Extraction spaces closed during the course of orthodontic therapy tend to re-open, whereas orthodontically rotated teeth are prone to relapse. One of the major causes of spaces opening between teeth is the supra-alveolar soft tissues which do not always adapt to the new tooth positions. Seven patients requiring extraction of upper first premolar teeth as part of their orthodontic treatment were selected for this study. Tattoo marks were placed in the attached gingivae close to the upper canine teeth. The canines were then retracted orthodontically across the extraction spaces. The left side was designated the control side and the right side the experimental side. Immediately after completion of retraction, the attached gingiva was surgically detached from the canine teeth on the experimental sides. The canines on both sides were retained in their new positions for 8 weeks following space closure. The amount of relapse or recoil of the gingivae was measured. In this study the gross gingival changes were similar to those described by Atherton and Kerr, Atherton, Edwards. The tattoo marks moved distally with the retracted canines. The amount of gingival movement was similar on both experimental and control sides and ranged between 49.4 percent and 82.4 percent of the retraction distance. Very little recoil or relapse of the gingivae occurred following surgical detachment from the canines. The results of this study indicate that the gingivae appear to adapt to the new tooth position and that relapse of canines retracted across extraction sites in the maxilla is not necessarily caused by the supra-alveolar soft tissues.

Adolescent↗