Dental plaque as a biofilm and a microbial community – implications for health and disease

Dental plaque is a structurally- and functionally-organized biofilm. Plaque forms in an ordered way and has a diverse microbial composition that, in health, remains relatively stable over time (microbial homeostasis). The predominant species from diseased sites are different from those found in healthy sites, although the putative pathogens can often be detected in low numbers at normal sites. In dental caries, there is a shift toward community dominance by acidogenic and acid-tolerating species such as mutans streptococci and lactobacilli, although other species with relevant traits may be involved. Strategies to control caries could include inhibition of biofilm development (e.g. prevention of attachment of cariogenic bacteria, manipulation of cell signaling mechanisms, delivery of effective antimicrobials, etc.), or enhancement of the host defenses. Additionally, these more conventional approaches could be augmented by interference with the factors that enable the cariogenic bacteria to escape from the normal homeostatic mechanisms that restrict their growth in plaque and out compete the organisms associated with health. Evidence suggests that regular conditions of low pH in plaque select for mutans streptococci and lactobacilli. Therefore, the suppression of sugar catabolism and acid production by the use of metabolic inhibitors and non-fermentable artificial sweeteners in snacks, or the stimulation of saliva flow, could assist in the maintenance of homeostasis in plaque. Arguments will be presented that an appreciation of ecological principles will enable a more holistic approach to be taken in caries control.     

Dental regeneration and materials—a partnership

Considerable focus on the biocompatibility of dental materials over the last three decades has provided a platform for a wealth of studies on the cellular and molecular responses of the cells of the pulp to injury, both from the disease process and from subsequent restorative intervention. These studies have been fundamental to understanding not only how we can achieve a biocompatible response during restoration of dental disease but also how we can exploit the pulpal cellular responses to achieve wound healing and tissue regeneration in the dentine–pulp complex. This article examines the responses of the pulp to injury and the events leading to tissue regeneration. As new biologically based regenerative therapies emerge for the dental tissues, it is important that these develop in partnership with more traditional approaches using dental materials.     

How to … Write and analyse a questionnaire

Abstract

Questionnaires are used in a wide range of settings to gather information about the opinions and behaviour of individuals. As with any other branch of science, the validity and reliability of the measurement tool, i.e. the questionnaire, needs to be rigorously tested to ensure that the data collected is meaningful. The design and method of administration of a questionnaire will also influence the response rate that is achieved and the quality of data that is collected. This paper discusses the issues that should be considered when designing and undertaking a questionnaire study.     

Pregnancy and periodontal disease--is there a relation?

Pregnancy complications, especially low birth weight (defined as birth weight less than 2.500 kilograms (kg)), pre-term delivery (less than 37 weeks) and pre-ecclampsia (elevated maternal blood pressure), continue to be a significant public health issue in both developed and developing countries. Recent data indicate that periodontal disease might confer risk for several systemic disorders. The relationship between periodontal diseases in pregnancy and obstetric complications has been increasingly investigated, showing inconclusive results. The purpose of this study is to review the current literature regarding the influence of periodontal status on pregnancy outcome, including the effect of periodontal treatment. Further research in this area is required, particularly with respect to the effect of population differences on this potential association between periodontal diseases and pregnancy complications as well as on the exact mechanism of this association. Since pregnancy tends to influence periodontal status, and considering the potential reported relation between periodontal disease and pregnancy complications, careful periodontal diagnosis and treatment before as well as during pregnancy is warranted.     

Azithromycin and dentistry - a useful agent?

OBJECTIVES: Azithromycin has recently replaced clindamycin oral suspension for prop hylaxis of infective endocarditis (IE) in children. It is also currently recommended by the American Heart Association as an alternative to penicillin, along with clindamycin for prophylaxis of infective endocarditis in adults. The objectives of this paper were to firstly, review the current literature on the efficacy of azithromycin as a suitable prophylactic agent in the prevention of infective endocarditis; and secondly, to review its pharmacological properties as a suitable therapeutic agent in the management of odontogenic infections. DESIGN: A review of the literature. CONCLUSIONS: The available evidence from animal models on infective endocarditis supports the efficacy of this drug as a prophylactic agent against oral streptococci. The pharmacological properties of this agent would make it a very promising therapeutic adjunct in the management of odontogenic infections. At present there are only a small number of studies available with valuable data on the efficacy of this relatively new drug. Further investigations comparing this compound with other commonly used adjuncts would be of great benefit.     

Interfacial and surface characterization of two self-etching adhesive systems and a total-etch adhesive after bonding to ground and unground bovine enamel—a qualitative study

The purpose of the study was to evaluate the enamel surface and interface morphology of two self-etching adhesive systems (SAS) vs a total-etch control, after bonding to ground and unground enamel using field emission scanning electron microscopy (FESEM). Thirty bovine incisors were used in this study. The buccal enamel surface of 15 teeth was ground flat to resemble freshly cut enamel. The rest of the teeth were left intact. Two SAS, Clearfil SE Bond (CSE, Kuraray) and Prompt L-Pop (3M-ESPE), and a conventional adhesive system, Scotchbond Multipurpose (3M-ESPE, control), were used to condition the surface of unground and ground enamel on 12 teeth. A composite button was bonded to the remaining 18 teeth; a cross-section (1 mm thick) was obtained from each and the bonded interface was polished. All specimens were dehydrated in ascending grades of ethanol, gold-sputter-coated, and observed under FESEM (Hitachi S-4000) to evaluate the ultrastructural morphology of the enamel surface and the enamel–dentin interface. The etching patterns and adhesive penetration varied according to the aggressiveness of the SAS, with CSE being the mildest and H₃PO₄ being the most aggressive. There were no significant differences on the ultrastructural morphology of the enamel surface between unground and ground specimens. It appears that microporosities within enamel prisms provide sufficient enamel–resin hybridization in unground enamel. The enamel dissolution pattern and depth of infiltration depend on the type of SAS used, with no significant differences in unground and ground enamel.     

Active and passive self-ligation—a myth?

Objective:To compare the frictional behavior of several self-ligating brackets with that of normal brackets both with and without tipping force-moments and in combination with different archwire dimensions.Materials and Methods:The resistance to sliding (RS) of seven self-ligating brackets, a conventional bracket, and a ceramic bracket with a low-friction clip were evaluated in combination with three different archwires and tipping force-moments of 0 and 10 Nmm. The center of rotation for the measurements was set within the center of the bracket or with a 10-mm offset. Resistance to sliding was measured using an Instron 3344 at a cross-head speed of 10 mm/min at a temperature of 36°C.Results:Without a tipping moment, RS increased with the active self-ligating brackets with increasing archwire size. No RS was found for any of the passive self-ligating brackets. The 10-Nmm tipping moment resulted in more RS and was similar for all bracket and archwire combinations. RS was approximately doubled when the center of rotation was located at the bracket rather than with a 10-mm offset.Conclusions:RS between brackets and archwires is highly dependent on the experimental setup. Different setups can result in contradictory results. Almost 1 N of traction force is lost in RS when a moment of 10 Nmm is placed at a rotational center 10 mm from the bracket.     

Sodium Hypochlorite and a Preparation Containing Glycocholic Acid and Surfactants Have a Synergistic Action on Organic Tissue Dissolution In Vitro

Introduction

The aim of this study was to evaluate porcine palatal mucosa dissolution by sodium hypochlorite (NaOCl) with or without an auxiliary dissolving agent containing glycocholic acid and a mixture of surfactants (Keratobacter [KB]; Saint Joseph DID, Valencia, Spain).

Cleft palate and bilateral congenital cataract: a familial observation: a new syndrome?

We report a family with a rare association of congenital bilateral cataract and cleft palate that has not to our knowledge been previously reported. The lineage has unveiled abnormalities over four generations affecting 21 people with congenital bilateral cataract, with or without cleft palate. The transmission seems autosomal dominant. Four brothers and sisters presented with this defect, and a fifth sister is healthy. The mother has facial dimorphism, congenital bilateral cataract, submucous cleft palate, clinodactyly, and scoliosis. The propositus' karyotype was normal. Array comparative genomic hybridisation (CGH) analysis showed an interstitial amplification in Xp21.1, found in the mother, in all the affected siblings but one, and in the healthy girl. Thisl association is not rare and has been reported in over 50 syndromes but rarely in familial observations. Based on the genetic-clinical discordance we wonder about the deleterious impact of the Xp21.1 amplification that might be a copy number polymorphism.     

Curing depths of a universal hybrid and a flowable resin composite cured with quartz tungsten halogen and light‐emitting diode units

This in vitro study evaluated curing depths of a universal hybrid resin composite with two viscosities (Tetric Ceram and Tetric Flow) after curing with 6 different quartz tungsten halogen and light‐emitting diode curing units. Irradiance (light intensity) of the curing units varied between 200 and 700?mW/cm ² . The curing units were used for standard, soft‐start, or pulse curing. Curing times were 20 and 40?s for standard curing, 3?+?10?s and 3?+?30?s for pulse curing, and 40?s for soft‐start. Resin composite specimens, 5 in each group, with a diameter of 4?mm and a height of 6?mm, were made in brass molds and cured from one side at a distance of 6?mm. After 2 weeks, the specimens were ground longitudinally half through the specimen. Curing depth was then determined by measurement of Wallace hardness for each half millimeter starting at 0.5?mm from the top surface. For all curing units and for both resin composites an increased curing time led to statistically significantly higher depth of cure (P?P?r?=?0.89, P?r?=?0.91, P?相似文献   

Multiple macrodonts with odontoma in a mother and son—a variant of Ekman-Westborg-Julin syndrome: Report of a case

A case of multiple macrodonts with a complex odontoma in a mother and son is reported. This condition is thought to represent a variant of the Ekman-Westborg-Julin syndrome. The authors discuss the relationship between macrodontia and odontoma, and the involvement of hereditary factors is suggested.     

Dentist and disability: a matter of occupational disease?

The incidence of and background to disability claims by dentists relating to 1999 are presented on the basis of data from Movir insurance company. Possible cases of occupational related disease are indicated. Claims resulting in more than 2 weeks sick leave have been received from almost 7% of the insured dentists (excluding pregnancy related sick leave). In nearly 30% of the cases, sick leave lasted for more than 1 year (particularly due to mental and musculoskeletal disorders). Compared to the figures for 1992 long-term health related absenteeism (longer than 365 days) has increased by as much as 155%. It is estimated that at least 15% of the claims are occupationally related. Based on the 1999 data a dentist would have approximately a chance of 50% for partial or complete premature retirement due to ill health.