Crouzon twins with cloverleaf skull malformations.

We describe unique monozygotic twins with Crouzon's disease and cloverleaf-shaped skull deformities who have been closely followed since birth. Their abnormal skull shapes were identified during antenatal ultrasound examination. The twins had gross exophthalmos and hydrocephalus with papilledema, so early calvarial decompression surgery was required. Although born to healthy parents of normal appearance, a third cousin of the twins had a milder form of Crouzon's disease, and there was a family history of high-arched palate on the twins' paternal side. Because Crouzon's disease is an uncommon condition and the cloverleaf skull shape is unusual in patients with Crouzon's disease, identical twins with this constellation of deformities must be exceptionally rare.     

Effect of orthodontic forces on blood flow in human gingiva.

The relationship of gingival blood flow to the magnitude and duration of applied force was studied in humans using Laser Doppler flowmetry. The sample consisted of five adult volunteers with interdental space between their maxillary central incisors. The labial surface of each central incisor was bonded with a buccal tube and a spring force was applied to close the space. The forces applied were 50 g, 80 g, 120 g, and 250 g. Each force was applied for 30 seconds, 60 seconds, 90 seconds, 5 minutes, and 10 minutes. The blood flow signals were recorded continuously using a pen recorder. Measurements indicated that blood flow was negatively correlated to the amount of force applied. The duration of reactive hyperemia was positively correlated to the duration of force. Laser Doppler flowmetry measures blood flow in superficial periodontal tissues. Yet, the relationship of blood flow changes to the magnitude and duration of orthodontic force suggests that measurements of gingival blood flow may provide a means of estimating physiologic orthodontic forces.     

The normal and diseased periodontium and periodontal disease activity

Scientific knowledge regarding the cellular and molecular biology of the periodontium in health is fundamental to the determination of how periodontal diseases begin and progress. Advances in diagnosis and treatment are in turn becoming increasingly dependent upon advances in the molecular biology of inflammation-induced changes in the periodontal tissues, and the regenerative capacity of the periodontal cells. New in vitro cell culture models, a broadening array of monoclonal antibody reagents, and general advances in scientific methodology have presented the field of periodontal research with excellent opportunities to explore the mechanisms of tissue destruction, as well as test innovative means to induce tissue regeneration. Laboratory and clinical findings in the past year have led to major expansions in how we perceive the pathogenesis of periodontal diseases, and also have altered our long-held beliefs about periodontal disease activity.     

Timing of first restorations in permanent teeth: a new system for oral health determination

Objectives: A system of oral health determination in which times between eruption of teeth and first restorations because of caries is measured is applied in a retrospective analysis of oral health data relating to rural health centres in Finland.

Method: The retrospective analysis was carried out using data relating to three health centres in different parts of Finland. The times between eruption and the placement of the first restorations in subjects up to 18 years of age were investigated.

Results: Between 10% and 25% of all permanent molar teeth were filled in the year of tooth emergence —the ‘immediate posteruptive step’. A steadily increasing restoration placement rate—the ‘ascending growth phase’—was observed after the ‘posteruptive step’. The restoration rate was found to plateau 5–8 years after eruption—the ‘retardation phase’.

Conclusions: Restoration increment curves with longitudinal measurements are believed to be a sensitive indication of oral health at both individual and population levels.     

Neurological deterioration after lumbar cerebrospinal fluid drainage.

Large-bore lumbar spinal fluid drainage is used frequently as part of the preoperative and intraoperative management of patients undergoing cranial base tumor resection. Such drainage allows displacement of the brain with minimal force, thereby potentially decreasing retraction damage to it. We document 2 patients in whom serious complications resulted from lumbar drainage systems. These patients deteriorated into a coma state following cerebrospinal fluid (CSF) drainage. Reinfusion of synthetic CSF solutions caused a brisk return to normal neurological status. These plus other potential complications associated with lumbar drainage, such as persistent CSF leaks into the back and soft-tissue nerve root injury, warranted abandoning the lumbar cistern drainage route of CSF drainage in favor of drainage directly from the intracranial compartment. Depending on the particular operation performed, drainage of CSF near the cribriform plate, the suprachiasmatic cistern, or from the sylvian fissure may be effective sites for CSF drainage. Unlike lumbar drainage, intracranial CSF drainage does not have the added risk of promoting cerebral herniation.     

A procedure for making a bruxism device in the office.

Microtrauma to the temporomandibular joint, the masticatory muscles, and the dentition can be significant in mandibular parafunctional activity such as nocturnal clenching and bruxing. Intraoral therapy can be useful in helping to reduce the deleterious effects of this activity. This article presents an in-office procedure for a device to reduce a delay in starting treatment and the time needed for adjustment of the device in the mouth.     

Bonding of plastic teeth to denture base resins.

This study evaluated the bond strengths of some new and traditional resin denture teeth and denture base resins. It included regular monolithic acrylic resin teeth (Bioform), monolithic acrylic resin-IPN teeth (Bioform IPN), and multilithic acrylic resin-composite resin teeth (Vivosit), with relatively new light-activated resin (Triad), conventional heat-cured resin (Lucitone 199), and autopolymerizing resin (Hygenic) denture base materials. The results of four-point flexure testing showed that the traditional materials gave the highest bond strength values. The autopolymerizing resin systems demonstrated interfacial failure with all resin denture teeth, showing that the common practice of treating teeth with the respective autopolymerizing monomer failed to produce adequate bond strength. Combinations of acrylic resin, IPN, and multilithic denture teeth with light-activated resins gave results calling for improvements in basic bonding system design, since interface debonding was prevalent. No failures occurred between the lap-ridge region of the multilithic tooth system and conventional heat-cured denture base resin.