Tooth stabilization for orthodontic retention.

This article reviews stability and retention of the orthodontically treated dentition. Factors and conditions that influence post-treatment stability are discussed. Methods for stabilizing and retaining the occlusion are reviewed.

Force degradation in elastomeric chains.

Elastomeric chains are a frequent choice for delivering forces required to close spaces orthodontically. Unfortunately, these forces degrade over time. Open and closed chains from six orthodontic suppliers were evaluated over time. For both types and for all suppliers, the greatest loss of force occurred within the first hour. During the next 2 to 4 days, forces delivered continued to fall but at a slower rate. Beyond that time, in general, forces delivered remain nearly constant but at a level lower than originally available. The amount of the force delivered at 28 days ranged from 85% to 30% of that available at the time of placement. At 28 days, gray chains from all suppliers delivered forces greater than 100 g.

Habits affecting dental and maxillofacial growth and development.

In concluding this discussion, it is apparent that altered oral function or rest position may have a significant influence on the developing orofacial region. In the case of non-nutritive sucking habits, the child's commitment and desire to stop the habit is important to the successful elimination of the habit. At times, a hands-off approach is our best approach. Other habits are managed by addressing their cause. We, as dentists, have the ability to influence this process through the proper identification and management of these problems.

Evaluation, diagnosis, and treatment of the traumatized patient.

This article discusses the early assessment of the patient who has sustained an oral injury. The various types of orofacial injuries are reviewed, with emphasis on their early management. The dentist's early assessment of the patient must include a general evaluation of the patient as well as a more specific dental evaluation because the general dentist is often the first person to assess a patient who has been injured.

Permeability of latex gloves after contact with dental materials.

The use of latex examination gloves in the dental office has become the standard of care. However, the effectiveness of gloves as a barrier after coming into contact with specific dental materials is still uncertain. To examine the effects of dental materials is still uncertain. To examine the effects of dental materials on latex, 100 latex examination glove finger tips were divided into 10 groups. Each group was manipulated in a different dental material for 15 minutes. Permeability was detected by the passage of herpes virus across the latex membrane, rinsed from the inner glove surface and titrated onto Vero cells. Significant virus leakage was discovered in gloves treated with acrylic monomer, chloroform, and orange solvent. Little virus leakage was noted in bleach, soap, and 30% phosphoric acid etchant treated gloves, and no virus leakage was found with composite resin, ethanol, formocresol, and water treated gloves. These data were supported with scanning electron micrographs taken of the treated glove samples and comparing with the controls. When certain dental materials are manipulated while wearing gloves, irreversible damage to the material occurs and may increase the practitioner's exposure to pathogens.

The role of the pediatrician in oral health care.

Many of the dental problems of childhood can be prevented if the physician recognizes and encourages good preventive habits, treats when indicated, and refers appropriately. With sound knowledge of health and disease of the oral and dental structures, the physician can enhance the chances of children growing up under optimal medical and dental conditions.

Managing common dental problems and emergencies.

This article discusses the more common oral and dental emergencies that children and adolescents may present to a physician. Many of these problems represent true emergencies that require immediate treatment or referral, whereas others are more common and less critical problems perceived by the child's parents as needing immediate attention. The problems presented in this article fall into three general areas: gingival and soft-tissue-related problems; problems related to teeth; and traumatic injuries to the teeth, their roots, and supporting structures.

Ultrasound demonstration of tongue motions during suckle feeding.

In this study the authors used ultrasound to demonstrate characteristic internal actions of the tongue during suckling. Its medial portion, into which the genioglossus is inserted, moves in relation to its lateral portions, into which the styloglossus and hyoglossus are inserted. A peristaltic wave of successive inferior and superior displacements moves posteriorly in the medial portion, compressing or 'milking' the nipple and propelling the expressed milk towards the pharynx. The lateral portions of the tongue enclose the nipple and the bolus and serve as reference for the displacements of the medial portion. These observations are related to anatomical studies of the tongue. The coordination pattern of suckle is compared with that of pharyngeal swallow. In instances where suckle and swallow are immediately sequential, the peristalsis which is common to both is continuous in the oral and pharyngeal portions of the food pathway.

The plan of the human face: a test of three general concepts.

In The Handbook of Facial Growth, Enlow proposes a series of anatomic concepts that account for "the plan of the human face." Three of those concepts are examined in this article, which presents measurements of 253 adult female primates from thirty-two species. As part of a system of craniofacial counterparts, Enlow proposes that the breadth of the mandibular ramus should equal the breadth of the pharynx. The relationship between ramus breadth and PNS-Ba in the primates studied strongly supports this hypothesis. A second concept tested concerns the relationship between prognathism and maxillary arch length. The relationship is not as strong as in the previous case, and some species are more prognathic than required for the size of their dentition. It is concluded that arch length and prognathism have an important biologic relationship but that the two features can vary with some independence. The third concept tested is the relationship between prognathism and interorbital breadth. Here the relationship is weak, and it is concluded that the interorbital breadth is not significant in setting a structural limit to the amount of facial prognathism.

Clenched jaw jerks in children.

Masseter muscle silent periods were assessed in 24 children divided into three groups according to their stage of dental development (primary, mixed, and permanent). Surface electrode EMG data, timing code, and microphone input were recorded on magnetic tape. A visual record was obtained by playing the tape into an optical oscillograph; measurements were made from the photosensitive paper. The results indicate the latency and silent period durations of clenched jaw jerks were similar among the three groups. For the subjects in this study, the mean latency and silent period durations of the masseter muscle during clenched jaw jerks were 14.9 ms (milli-seconds) and 27.0 ms.

Parameters of open-close-clench cycles in children.

The results of this study indicate that the latency and silent periods of OCC cycles do not vary among groups representing distinct dentitional stages. The mean latency period durations obtained from the OCC cycles of the subjects in this study ranged from 16.6 to 19.5 msec and demonstrated the smallest SD of all parameters measured. The mean silent period durations ranged from 11.6 to 15.4 msec. Since the neurophysiologic responses do not vary, the reflex elicited by tooth contact in OCC cycles is not based on tooth form or quantity. The results further indicate that, with the exception of the latency period of the anterior temporal muscles, the activities of the right and left components of the masticatory muscles examined are significantly correlated to each other during OCC cycles. This suggests a role for the anterior temporal muscle in bringing about adjustments of the masticatory system in the intercuspal position.

Dentigerous cyst with mural ameloblastoma.

A case of a 14-year-old black girl with a lesion that appeared to be a dentigerous cyst is presented. Radiographic appearance, findings of a bone scan and biopsy by aspiration are discussed. Histologic findings showed that the lesion was an ameloblastoma that is believed to have arisen from the dentigerous cyst wall.