Nickel ion concentrations in the saliva of patients treated with self-ligating fixed appliances: a prospective cohort study

Abstract

OBJECTIVE Orthodontic appliances are considered to be highly biocompatible although adverse effects attributed to the release of nickel ions (Ni(2+)) have been documented. Self-ligating brackets have grown in popularity for economic reasons and supposed friction reduction. The aim of the present prospective cohort study was therefore to determine salivary Ni(2+) concentrations in patients undergoing orthodontic treatment with self-ligating fixed appliances. MATERIALS AND METHODS A group of 30 patients between 10 and 13 years of age were treated with self-ligating brackets (SmartClip™), molar bands, and nickel-titanium (NiTi) archwires. Unstimulated saliva samples were collected after different time points (before treatment, after self-ligating bracket and band placement, before archwire insertion, after archwire insertion, and finally 4 and 8 weeks afterwards) and analyzed with an ICP mass spectrometer followed by generalized estimating equation modelling with = 5 %. RESULTS The baseline median salivary Ni(2+) concentration was 21.85 µg/l, while the Ni(2+) concentrations at the following visits ranged between 13.73 and 85.34 µg/l. Significant increases in Ni(2+) levels compared to the baseline levels were detected after band/bracket placement [+59.76 µg/l; 95 % confidence interval (CI) 44.88-74.64 µg/l; P < 0.001] and after archwire insertion (+53.55 µg/l; 95 % CI 25.57-81.52 µg/l; P < 0.001). After 4 weeks, Ni(2+) concentrations returned to initial control levels or were lower. CONCLUSION Self-ligating orthodontic appliances may affect salivary Ni(2+) concentrations in vivo over the short term. However, levels resembled those documented in conjunction with conventional bracket use and remained below the daily dietary Ni intake. 2 Abstract Background and objective: Orthodontic appliances are considered to be highly biocompatible,

Caspase-3 as an important factor in the early cytotoxic effect of nickel on oral mucosa cells in patients treated orthodontically

“…Such alloys are mainly composed of 68-80% nickel and 12-26% chromium but they also contain other elements in quantities varying from 0.1 to 14% [1,2]. Recent studies indicate an increased release of nickel from orthodontic appliances into the artificial saliva or into human salivary secretions [3][4][5]. Moreover, a few studies have demonstrated a positive correlation between the enhanced nickel concentration in oral mucosa cells released from fixed orthodontic appliances and DNA damage as well as increased number of apoptotic cells [6,7].…”

Nickel hypersensitivity and orthodontic treatment: a systematic review and meta‐analysis

“…Nickel-containing alloys exist in a wide variety of appliances and auxiliary devices used in orthodontics, with a content of up to 55% by weight. Likewise, the in vivo release of nickel ions varies greatly, from 0.5 to 105.7 μg/l, according to the alloy type, body fluid, temperature, mechanical stress, or pH (8,9). In general, orthodontic materials are considered to be highly biocompatible (10).…”

Corrosion Resistance of Stainless Steel Brackets After Thermal Recycling by Direct Flaming

“…Stainless steel brackets are the most widely used due to their good mechanical properties, corrosion resistance and biocompatibility [1]. Despite their high corrosion resistance, stainless-steel brackets can corrode in the oral environment [4].…”

“…Stainless-steel brackets remain in patients' mouths for extended periods, during which the brackets are exposed to chemical and physical processes that can damage the metal structure, resulting in decreased corrosion resistance [1,2]. A study indicated that in addition to environmental conditions in the oral cavity, thermal recycling (direct flaming) can affect the stability of the metal ion content of the bracket, resulting in the release of metal ions and the decrease of corrosion resistance of the bracket [3].…”