George Black explains why it makes sense to choose fluoride-releasing restorative materials
The role of fluoride in the prevention of dental caries is well-known in the dental profession and the use of fluoridated toothpastes and mouthwashes is widespread in UK households. The benefits of fluoride when it comes into contact with tooth enamel were discovered at the beginning of the 20th century in the USA when residents of an area in Colorado with high levels of fluoride naturally present in the drinking water were found to have a surprisingly high resistance to tooth decay, as well as rather unpleasant brown stains caused by fluorosis on the surface of their teeth.
This accidental discovery led to further research and water fluoridation studies which validated the initial observations and led to widespread water fluoridation programmes across many US states, a timely intervention as the national diet evolved to incorporate more and more sugar over the ensuing decades.
The presence of more sugar in the oral cavity leads to increased levels of organic acids such as lactic acid, which destabilise the natural balance of mineralization and remineralisation in the hydroxyapatite phase of the tooth. According to studies, the presence of lactic acid at the tooth surface enhances the rate of demineralization relative to that of remineralisation leading to a loss of hydroxyapatite from the mineral phase and resultant tooth decay.
A defence against sugar-fuelled acid attack
During an acidic challenge, fluoride is able to absorb to the surface of the apatite crystals, inhibiting demineralisation. Then, when pH is re-established, the fluorohydroxyapatite from fluoride speeds up the remineralisation process and the new mineral contains higher levels of fluoride as opposed to carbonate which renders the enamel more resistant to future acidic attack.
These benefits have made the topical application of fluoride directly onto tooth enamel a widespread practice, in the form of fluoride-containing toothpastes, mouthwashes and the regular application of fluoride varnish by dental professionals, especially on children’s teeth.
Many restorative materials now also boast fluoride-releasing properties which are designed to protect tooth tissues from demineralisation in the region around the restoration, an important benefit in the face of ongoing evidence that secondary caries are the principal reason for restoration failure in both permanent and primary dentition.
When choosing the right restorative composite for their practice, clinicians tend to have a long list of must-haves which typically include: excellent adaptation, easy handling, good translucency, and smooth flowability to enable the clinician to achieve a functional restoration; high compressive strength, low polymerization shrinkage, low microleakage and high biocompatibility to ensure durability; and a wide range of shades and high polishability to deliver excellent aesthetics and natural-looking results.
Many clinicians are seeking to increase their chances of ensuring a durable restoration by choosing a composite which releases fluoride over several months or even years to maintain a higher presence of fluoride in the oral cavity, particularly around the restoration, to reduce the risk of secondary caries.
A multi-purpose hybrid glass ionomer composite such as Geristore Paste, is one such composite, combining the best properties of both types of materials for class III and V restorations. Its self-adhesive properties make it easy to use with no need for retentive cavity design, helping eliminate chair time usually devoted to cavity preparation whilst saving tooth structure, which can prove ideal with paediatric or geriatric patients.
There are fluoride-releasing cements also available, such as Infinity, an all-purpose, self-adhesive cement base/liner. Both Geristore Paste and
Infinity benefit from years of clinical success in terms of durability and safety and a wide range of applications making them an effective and convenient choice for composite restorations that will last.
Dental clinicians have enough considerations to contend with when choosing the right restorative materials. Dentistry can be made a little easier by increasing the chances of keeping dental caries at bay by choosing fluoride-releasing materials for dental restorations.
Article originally published in The Dentist magazine [February 2018]