Peri-implantitis and titanium corrosion
Peri-implantitis is a multifactorial condition related to implant placement, host response, blunt trauma, prosthetic design, poor oral hygiene, bone loss, gingival recession, and exposure of the dental implant to the oral environment. Disinfection of the implants, transplantation to reconstruct the peri-implant supporting structure are common treatments.
Titanium and zirconia dental implants are commonly used for their biocompatibility and durability. Titanium implants are more popular in the US due to their affordability, high strength and corrosion resistance.2
Corrosion of titanium dental implants has been associated with implant failure and is considered one of the triggers for peri-implantitis.3 Recent studies suggest that erosion may be associated with the progression of peri-implantitis by causing microbial dysbiosis.4 Corrosion products and metal ions resulting from metal dissolution can lead to adverse tissue reactions in the oral environment. What is more concerning is the effect on osseointegration. regeneration may not occur once surface passivation is lost.3
There is concern that the use of fluoride may contribute to the erosion of dental implants. Critics of fluoride treatments, or even fluoride toothpaste, warn of the risk of corrosion over time.
A study showed corrosion in a titanium alloy commonly used in orthodontic wires, not dental implants, with acidified fluorophosphate (APF) gel. This leads to a recommendation for implant patients to avoid fluoride with a high acidic pH, such as APF fluoride gel.
It has been shown that fluoride can cause corrosion of exposed dental implant surfaces in the presence of acidic pH.6 Therefore, salivary pH conditions should be taken into account when administering prophylactic effects of NaF and SnF2 fluoride varnishes.7,8
What are the safe pH ranges for using fluoride in titanium implants?
In 1998, confined fluoride ions showed the corrosion process in titanium once the pH dropped below 3.5.9 Fluoride-containing solutions (pH 7.0) did not damage the cast pure titanium (CP Ti) surface and can be used by patients with titanium-based restorations.10 This data instructs us to monitor the pH of both product and saliva in a safe range between 3.5 and 7.0 pH.
Some believe that OTC low pH neutral fluoride products can be safely used on titanium dental implants if the pH of the saliva is controlled. The concern is that patients with a high rate of caries who receive prescriptions for high-concentration fluoride products usually have an acidic pH. The high fluoride concentration and acidic pH in toothpaste used to prevent caries can modify the surface structure of titanium implants.11
Individual patient assessment is vital. We should tailor recommendations for patients with mixed dentition with titanium implants and natural teeth with multiple fillings based on patient needs and risk factors. Hygienists should focus on alternatives to reduce caries by balancing salivary pH or recommend xylitol products over high-concentration fluoride formulations to prevent erosion of dental implants. Educating patients about factors that contribute to high salivary pH, such as dietary habits and rinsing after eating acidic or sugary foods, can minimize the risk of tooth decay.
Regular application of fluoride can be part of a comprehensive oral hygiene regimen. Fluoride helps strengthen natural teeth and reduce the risk of tooth decay. By maintaining the health of adjacent teeth, fluoride varnish contributes to the overall health of the mixed dentition.
Dental hygienists should consider incorporating salivary pH testing to monitor safe fluoride use for dental implant patients. Daily use of high-concentration prescription fluoride combined with prolonged exposure to the acidic pH of saliva can lead to erosion or damage to the implant surface. Neutral sodium or stannous fluoride varnish treatments administered by a dental professional in controlled amounts have a lower risk of adverse effects on dental implants if administered at neutral salivary pH. More research is needed on this topic.
