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Biomedical subjects

E P Hicks

Publications and source records attributed to E P Hicks.

At least 19 recordsLinked to original sources
PubMed2000

Early orthodontic treatment: what are the imperatives?

BACKGROUND: Then authors provide a critical review of the issues involved in determining the appropriate timing of orthodontic treatment. Both single- and two-phase treatments are discussed and guidelines are offered to assist in formulating treatment plans. OVERVIEW: In providing orthodontic care for pediatric patients, clinicians often question whether to begin treatment early--during the primary or early-transitional dentition--or wait until all or most of the permanent teeth are present. The authors review the most current literature (from 1991 to 1999), including several recently completed and ongoing randomized clinical trials, to critically evaluate the effectiveness of each approach. PRACTICAL IMPLICATIONS: The controversy surrounding early vs. late orthodontic treatment is often confusing to the dental community. This article reviews both sides of the issue for orthodontic treatment of Class II and III malocclusions, as well as for the management of Class I crowding and problems in the transverse dimension. Early orthodontic treatment is effective and desirable in specific situations. However, the evidence is equally compelling that such an approach is not indicated in many cases for which later, single-phase treatment is more effective. Therefore, clinicians must decide, on a case-by-case basis, when to provide orthodontic treatment. For many patients, delaying treatment until later in their dental and skeletal development may be advisable.

Adolescent↗
PubMed1999

Third molar management: a case against routine removal in adolescent and young adult orthodontic patients.

In the nearly two decades since the National Institutes of Health conference, controversy and uncertainty have continued with respect to the diagnosis and treatment of impacted, nondiseased third molars in adolescents and young adults. Articles published over the past 10 years have studied the issue from the vantage point of risk management. Those who favor prophylactic removal justify this action on three premises: 1. All impacted third molars are potentially pathologic; therefore, prophylactic removal reduces or eliminates risk of future disease. 2. The presence of third molars can cause late crowding. 3. Removal during adolescence and young adulthood reduces risks of operative and postoperative complications compared with older patients. Those who favor conservative management offer three counter arguments: 1. Although impacted third molars do pose a risk of a pathologic condition, the risk is relatively small in comparison with the risks of operative and postoperative complications and the costs of unnecessary removal. 2. Although some investigators have shown a statistical association of third molars and late anterior crowding, the association is not strong enough to allow prediction of patients at risk. This is due principally to the high degree of individual variability, suggesting that many other factors interact in the development of postadolescent crowding. 3. Although studies have shown that morbidity is reduced when impacted, nondiseased third molars are removed during adolescence or young adulthood, the cost-risk-benefit data do not justify routine removal. Proponents of prophylactic removal argue that the benefits outweigh the risks. Proponents of conservative management argue that the scientific evidence is inconclusive in support of prophylactic removal. Unfortunately, much of the clinical research has been flawed. This has led to contradictory interpretations that have not fully clarified the relative risks and benefits of early intervention. Untrustworthy data have served only to fuel the debate and controversy concerning proper protocols. However, careful analyses of the published research show that routine removal of impacted or unerupted, disease-free third molars cannot be justified. A case-by-case management protocol that requires monitoring development represents the consensus of most researchers in this field.

Adolescent↗
PubMed1997

A prospective study of lip adaptation during six months of simulated mandibular dental arch expansion.

The stability of dental arch expansion with conventional orthodontic treatments is disappointing. An increase in labial soft tissue pressure resulting from the expansion may contribute to this instability. An 8-month study of lip pressure changes resulting from lip bumper wear has been conducted, but no long-term studies have been conducted on pressure changes resulting from conventional expansion using fixed appliances. The purpose of the current study was to investigate changes in labial soft tissue pressures when conventional expansion was simulated. Twenty-two subjects wore a stent simulating mandibular dental arch expansion. They were instructed to wear the stent full-time. Lip pressure was recorded initially at 1 week, and monthly for 6 months. A repeated measures ANOVA was used for statistical analysis. A statistically significant (P < or = 0.05) increase in pressure was documented after initial insertion of the expansion-simulating stent. The increase was not maintained, suggesting an adaptation of the labial soft tissues.

Adaptation, Physiological↗
PubMed1996

Lip adaptation to simulated dental arch expansion. Part 2: One week of simulated expansion.

An increase in resting lip pressure and the resulting disruption of the intraoral pressure equilibrium may be responsible for the poor stability found with orthodontically expanded dentitions. Passive expansion strategies seek improved stability by altering lip pressure, thus creating a new equilibrium. One of these strategies has been shown to alter pressure favorably. However, pressure changes associated with conventional expansion need to be studied before conclusions regarding the superiority of passive expansion can be drawn. The purpose of this study was to examine lip pressure changes after 1 week of simulated conventional expansion. Twenty-two subjects agreed to wear a mandibular expansion-simulating stent full-time for 1 week. Resting pressure was measured in the midline and right canine areas. Midline lip pressure decreased significantly after 1 week. Resting pressure was measured in the midline and right canine areas. Midline lip pressure decreased significantly after 1 week while pressure in the canine area did not change significantly. This finding suggests an adaptive response that varies according to anatomic location.

Adaptation, Physiological↗
PubMed1995

Reliability of the Bolton tooth-size analysis when applied to crowded dentitions.

The Bolton tooth-size analysis is widely taught and used in orthodontics. However, its reliability has not been documented. The purpose of this study was to evaluate the reliability of the analysis when performed with needle-pointed dividers and a Boley gauge. Four clinicians measured the teeth on 15 sets of casts with two instruments at two sessions. The measurements were used to calculate tooth-size excess. To evaluate the measurement error, the difference between the two analyses made by the same investigator on the same set of casts was calculated. More of the same-investigator analyses were significantly correlated when the Boley gauge was used than when the needle-pointed dividers were used. Between-investigator analyses revealed significant correlations for each measurement session with both instruments. Every investigator was found to have at least one measurement error for each analysis and with each instrument that was as large as a clinically significant result of a Bolton analysis. The results of this study demonstrate that clinically significant measurement errors can occur when the Bolton tooth-size analysis is performed on casts with at least 3 mm of crowding. The Boley gauge demonstrated a higher frequency of significantly correlated repeated measures and thus may be somewhat more reliable for this analysis than the needle-pointed dividers.

Cuspid↗
PubMed1989

Effect of systemic fluoride on rat molar morphology. Stereophotogrammetric analysis.

Female Sprague-Dawley rats were divided into three groups. All three groups were given the same solid diet (with 1.6 ppm F). Group I was given deionized water, group II drank water with 5 ppm fluoride added, and group III had 50 ppm fluoride added. All females were mated with the same male. The pups were sacrificed at 28 days, and the mandibles were removed and cleaned. Three-dimensional representations of the occlusal surfaces of the 1st and 2nd mandibular molars were reproduced via computer-digitized images using stereophotogrammetry. Fissure depths and widths were measured, and 'volumes' of the fissures were computed. The fissure widths, depths, and volumes were compared statistically using unpaired t tests between groups (p less than 0.05). There were significant differences in fissure depth between groups I and II and between groups I and III. For fissure volumes, significant differences were found between groups I and III. The width of the fissure and the overall tooth size were not significantly different between fluoride-treated groups. Standardization showed a reproducibility to within +/- 40 mm with the stereophotogrammetric method.

Animals↗
PubMed1988

Intraventricular administration of interferon and administration of methisoprinol by mouth in the treatment of adult-onset subacute sclerosing panencephalitis.

This is thought to be the first report of the use of interferon therapy by intraventricular administration in adult-onset subacute sclerosing panencephalitis. A 22-year-old female patient with subacute sclerosing panencephalitis was treated for three months with interferon by the intraventricular route and methisoprinol (inosiplex) by mouth. There was no obvious clinical improvement during this time, and the cerebrospinal-fluid measles antibody titre remained elevated. The lack of effect of therapy could be attributed partly to the patient's age and to the rapidly progressive deterioration in her condition before treatment. No significant side-effects were associated with this therapy. Further trials of these medications in adult-onset subacute sclerosing panencephalitis are indicated.

Administration, Oral↗
PubMed1984

Narcolepsy, paranoid psychosis, major depression, and tardive dyskinesia.

This report describes a man with narcolepsy, paranoid psychosis, major depression, and tardive dyskinesia. The case illustrates the treatment difficulties such a patient presents and also raises questions about interactions between the putative neurotransmitters involved in each of these conditions. It is suggested that the presence of narcolepsy may facilitate the appearance of unwanted effects of antidepressants and neuroleptics such as psychosis and depression.

Aged↗
PubMed1979

The neurological aspects of atrial myxoma.

2 cases of left atrial myxoma are presented, with a review of the recent literature on the topic, in order to bring this rare condition to the attention of clinicians. Both cases presented to the Neurological Unit of the Queen Elizabeth Hospital during 1978. The cases helped to emphasise the role of echocardiography in the routine appraisal of the stroke patient, especially if there are multiple lesions or if the patient concerned is young. The second case raised interseting questions regarding electrocardiographic changes associated with altered states of consiousness. Until recently cardiac myxomas were usually a postmortem diagnosis, but now with the effective combination of echocardiography and cine-angiography, cases are being effectively diagnosed and treated. It is hoped that with an increased awareness of the condition, diagnosis will be made sooner and thus prevent more severe sequelae occuring.

Adult↗
PubMed1979

Carbamazepine in two pregnancies.

2 patients with epilepsy in pregnancy are described. Both received carbamazepine prior to conception, and during the greater portion of the first trimester. Both had partial and generalised epilepsy of late onset. Case 1 resulted in stillbirth at 25 weeks' gestation. The malformations included closely set eyes, atresia of multiple hollow viscera, and non-fusion of the mandible without hare lip or cleft palate. A possible interaction with a compound analgesic is discussed. Case 2 resulted in a normal baby. The literature, although favouring carbamazepine in pregnancy, is not yet sufficiently decisive to indicate a clear preference between no treatment and carbamazepine with carefully monitored serum levels for epilepsy in pregnancy. This study emphasises the need for continued pooling of data, and for added caution when there is a history of fetal malformation or obstetric problems. The teratogenicity of carbamazepine is neither confirmed nor denied by this limited study.

Abnormalities, Drug-Induced↗
PubMed1975

The effects of fluoride on the mineralization of embryonic chick tibiae in organ culture.

The effects of various concentrations of fluoride on the mineralization of embryonic chich tibiae were studied in vitro. After 4 days incubation in medium with a physiological Ca x PO4 product (1.8 mM2), fluoride promoted a highly significant dose-related enhancement of bone mineralization. In experiments where the medium Ca x PO4 product was varied by changing either Ca or PO4 while keeping the other constant at 1.8 mM, fluoried at 7.5 muM or at 100 muM affected bone mineralization differbntly at low and high products. At medium Ca x PO4 products below 3 mM2, fluoride significantly enhanced bone mineral deposition compared to paired control bones, while at products above 5 mM2, fluoride significantly inhibited bone mineralization. This dual effect of fluoride was observed in both live bones and bones metabolically inhibited by 1 mM iodoacetic acid. Comparison of the effects of fluoride on the mineralization of live and dead bones suggested that the effects are dependent on the cellular control of Ca x PO4 product in the bone extracellular fluid. These findings support the hypothesis that fluoride may play an important role in governing the rate of mineralization in growing bones.

Animals↗
PubMed1975

The rectal administration of lactulose.

A lactulose colonic washout (pH 4.5) was administered to six male patients with portal systemic encephalopathy. Estimation of blood ammonia levels and electroencephalography were performed before and after each treatment. Five patients recorded a significant fall in blood ammonia level as a result of lactulose therapy (P less than .025). In the sixth subject, an enema with buffered physiological saline, pH 4.5, induced a fall in ammonia which was not increased by subsequent lactulose solution. Improvement in the electroencephalogram was recorded in all periods where a lactulose colonic washout produced a fall in blood ammonia level.

Aged↗
PubMed1975

Enteric coated levo-dopa in clinical practice.

The results of a clinical trial of enteric coated Levo-dopa are described for nineteen patients with Parkinsonism. Twelve cases comprise the nuclear group and all were intolerant to therapeutic doses of standard Levo-dopa. Seven cases were receiving Levo-dopa for the first time. Treatment periods ranged from three to twelve months. Of the whole group, 84% have improved. Of the poor responders to standard Levo-dopa 58% have improved markedly and the remaining 42% have improved to a moderate degree using clinical criteria. The mean stabilization dose was 1.5 grams daily and using the Mann-Whitney U test the difference is highly significant when comparison is made with the stabilization dose of 3.0 grams for standard Levo-dopa (P less than .001). The method of stabilization is described; the commonest initial stabilization period is three weeks. Side-effects are dose-related. No side-effects have appeared in 60% of the patients and only mild or transient side-effects have appeared in 20%. A characteristic toxic reaction is described. This enteric-coated preparation of the drug appears to control the "on-off" phenomenon in at least 50% of cases with this problem. The preparation is suitable for routine use in outpatients but added care is required to ensure that vitamin tonics are rigorously avoided. Two deaths are recorded during the trial, but analysis shows them to be unrelated causally to the therapy. Enteric coated Levo-dopa is recommended as the primary treatment in all new cases where Levo-dopa therapy is indicated. No adverse interactions have occurred with other commonly used anti-Parkinsonian drugs.

Adult↗