Protection of the lip from the activator arm of maxillary distractors

The long spring-loaded distractor arms of maxillary distraction devices can cause pain and ulceration of the upper lip. We describe a simple method to relieve the tension and discomfort on the soft tissues using Silastic tubing.     

Remineralization of deep enamel dentine caries lesions

Enamel remineralization is generally studied in superficial (up to 100 mum) lesions, but in vivo caries lesions may be tenfold deeper. This article addresses the question whether deep lesions, and extending into dentine, can be remineralized under optimal conditions and if this process is influenced by agents affecting calcium phosphate precipitation and dissolution. Lesions through enamel into dentine were first formed in thin sections and then continuously remineralized for periods up to 200 days. With longitudinal assessment by transversal microradiography it was showed that remineralization throughout the depth of the lesion and into the dentine was possible, although this process is very slow. Fluoride and bisphosphonate treatments affected mainly the deposition in the outer enamel. Although it was assumed that this would affect the diffusion of ions to deeper layers, the treatments had no impact on remineralization in the inner enamel or dentinal parts of the lesions. These findings are discussed with relevant theoretical considerations, and in their possible clinical implications.     

Dental caries: a dynamic disease process

Abstract Dental caries is a transmissible bacterial disease process caused by acids from bacterial metabolism diffusing into enamel and dentine and dissolving the mineral. The bacteria responsible produce organic acids as a by-product of their metabolism of fermentable carbohydrates. The caries process is a continuum resulting from many cycles of demineralization and remineralization. Demineralization begins at the atomic level at the crystal surface inside the enamel or dentine and can continue unless halted with the end-point being cavitation. There are many possibilities to intervene in this continuing process to arrest or reverse the progress of the lesion. Remineralization is the natural repair process for non-cavitated lesions, and relies on calcium and phosphate ions assisted by fluoride to rebuild a new surface on existing crystal remnants in subsurface lesions remaining after demineralization. These remineralized crystals are acid resistant, being much less soluble than the original mineral.     

Oral cancer awareness for the general practitioner: new approaches to patient care

In Australia, oral cancer accounts for approximately 2-3 per cent of all cancers, and approximately 1 per cent of deaths from cancer. The incidence of intra-oral cancer is gradually increasing. It is now well established that early detection of potentially malignant disease can improve the clinical outcome for patients, and as such it is the responsibility of dentists to identify such lesions early. To facilitate early detection of suspicious oral lesions several clinical methods of detection can be used. In addition to conventional visual screening of oral tissues with the naked eye under projected incandescent or halogen illumination, there are many clinical diagnostic aids that can be undertaken to help detect oral cancer. In this article we explore clinically available modalities that may be used by the general dental practitioner, and highlight their inherent strengths and weaknesses.     

An ultrastructural and immunohistochemical study of human dental pulp: identification of Weibel-Palade bodies and von Willebrand factor in pulp endothelial cells

Special and specific immunohistochemical techniques as well as routine transmission electron microscopy were used to identify the presence of von Willebrand factor (vWF), a blood clotting factor essential to normal hemostasis, and Weibel-Palade bodies (WPB's), respectively, in the endothelial cells lining the blood vessels from both normal and inflamed human pulpal tissues. In human endothelial cells, WPB's are peculiar and specialized organelles which store vWF. All classes of blood vessels (capillaries, arterioles, arteries, venules, and veins) were vWF positive. The fine structural studies showed similar results with regard to the presence of WPB's. Interestingly, morphometric analyses conducted on the same tissues using either light or transmission electron microscopy showed that significantly more vWF-positive blood vessels were seen in the inflamed tissues. In agreement with the latter observation, transmission electron microscopy showed that more vascular endothelial cells contained WPB's in the inflamed tissues when compared with the normal tissues. From this it appears that during pulpal inflammation, the cascade of events associated with hemostasis may be activated with the increased synthesis and release of vWF by endothelial cells.     

Effects of pharmacologic reductions in salivary flow on taste thresholds in man

The effects of short-term salivary flow reductions on human taste thresholds were measured. Recognition and detection thresholds were obtained from 65 subjects during periods of both normal and reduced salivary flow. Decreased salivary flow was achieved by oral administration of either Elavil, Benadryl or atropine. Thresholds were measured for NaCl, citric acid, quinine sulphate and sucrose with a traditional series of aqueous solutions as well as with a series of dry taste stimuli using a filter-paper base. Whole mouth resting flow and stimulated salivary flow were measured before and after taste testing. The pharmacologic agents produced depressions in salivary flow ranging between 30 and 75 per cent of normal levels. The large decreases in flow produced no measurable changes in taste thresholds with the exception that an increased sensitivity to aqueous and dry citric acid stimuli consistently was observed following atropine administration. Changes in salivary bicarbonate levels, produced by atropine, may have mediated the observed shifts in oral sensitivity to citric acid.     

Use of a Reflectance Spectrophotometer in Evaluating Shade Change Resulting from Tooth-Whitening Products

Historically, shade change assessment associated with vital bleaching treatment regimens has been visually evaluated through the use of shade guide tabs. Innovations in the industry of dentistry have brought forth new technologies capable of measuring such changes via the capture and analysis of reflected wavelengths of light.
CLINICAL SIGNIFICANCE
This article introduces the use of a 45/0 reflectance spectrophotometer and identifies the advantages and limitations associated with such a technology in the assessment of shade change owing to vital bleaching.