Palatal rugae morphology is associated with variation in tooth number.

This observational study compared palatal rugae morphology in adolescent subjects with normal tooth number and tooth agenesis. Maxillary dental study casts were used to compare rugae number, length and shape. Each study group contained 60 subjects (30 females and 30 males) mean age 13.4 (SD, 1.55) in control and 13.56 (SD, 1.54) years in tooth agenesis groups (p = 0.576). Mean number of missing tooth units in the tooth agenesis group was 2.1. Mean number of primary rugae in the whole sample was 4.35 (SD, 0.98) on the right and 4.33 (SD, 0.92) on the left with no significant differences (p = 0.236 and p = 0.404, respectively). However, the number of secondary rugae on the left (p = 0.006) and fragmentary rugae on the right (p = 0.004) was significantly increased in the tooth agenesis group. The shape of left primary rugae 2 and 3 also differed between groups, tending towards a wavy pattern in the control group and curved in the tooth agenesis group (p = 0.012 and p = 0.004, respectively). In addition, primary rugae 3 was more convergent (p = 0.008) whilst left primary rugae 3 and 5 were orientated in an antero-posterior direction (p = 0.04 for both rugae) in the tooth agenesis group. Subgroup analysis also identified significant associations between patterns of tooth agenesis and rugae number, in addition to shape of primary rugae. The identification of significant differences in rugae pattern between subjects with normal tooth number and agenesis suggests potential commonality in signal pathway disruption during establishment of these structures.

The Hawlix: a simple and aesthetic prosthetic- orthodontic retainer.

This report introduces the Hawlix, a hybrid thermoformed and cold-cured retainer. It was developed to overcome the limitations that modified Hawley retainers possess when used in patients with bounded saddles, attributable to dental trauma or hypodontia. The Hawlix can be used as an intermediate retainer while a patient is waiting to receive restorative treatment. Some of the advantages of the Hawlix over the modified Hawley retainer include: superior aesthetics, cost-effectiveness, ease of manufacture, adequate resistance to fracture, preservation of a residual ridge, and precise space maintenance.

A study of nasal respiratory resistance and craniofacial dimensions in white and West Indian black children

Two studies have shown that there are morphologic differences in the nasopharynx between the major racial groups. This investigation was conducted to see whether these morphologic differences affected nasal respiration. Twenty-two West Indian and 24 white children (mean age of 13 years 11 months) were studied to examine the relationship between nasorespiratory function and nasopharyngeal and dentofacial structure. The nasorespiratory function was measured in terms of nasal respiratory resistance, NRR, (Pascals/cm3 per second), both by anterior and posterior methods, with a computerized rhinomanometer. Nasopharyngeal structure described in terms of cephalometric variables. The West Indian cephalometric profile generally conformed to its existing description in the literature including prognathic jaws and bimaxillary proclination; in addition, the West Indians were found to have a greater bony nasopharyngeal width (posterior nasal spine-basion) and shallower nasopharyngeal roof angle (posterior nasal spine-hormion-basion). All rhinomanometry were significantly lower in the West Indian group, especially when posterior rhinomanometry was used. The correlation coefficients between the cephalometric and the rhinomanometric measurements were statistically significant but low. In addition, the measure of mandibular prognathism (angle SNB) was also found to be significantly correlated with the nasorespiratory resistance (AU)