Optimal photoactivation time and thermal behavior of gingival barriers used in in-office dental bleaching

IF 4.8 2区医学 Q1 DENTISTRY, ORAL SURGERY & MEDICINE

Journal of dentistry Pub Date : 2025-06-13 DOI:10.1016/j.jdent.2025.105888

Michael Willian Favoreto , Michel Wendlinger , Laryssa Mylenna Madruga Barbosa , Gabriel David Cochinski , Vinicius Borges Oliveira , Cesar Augusto Galvão Arrais , Alessandra Reis , Alessandro D. Loguercio

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引用次数: 0

Abstract

Objective

To evaluate the influence of exposure time and curing distance on the degree of conversion (DC) and temperature change of light-cured gingival barrier materials.

Methods

An in vitro study was conducted with 576 disk-shaped specimens, divided into 72 groups (n = 8) based on three factors: gingival barrier type (SDI Gingival barrier, DMC Lase Protect, Ultradent OpalDam, PHS Potenza Blocco, FGM Top Dam, DFL Total Blanc Protetor Gengival), irradiation time (3, 5, 10, 15, 20, and 30 s), and curing distance (Valo, Standard Mode: 1 mm [900 mW/cm²] or 10 mm [450 mW/cm²]). DC was assessed by micro-Raman spectroscopy. Thermal changes were assessed using a T-type thermocouple on simulation model. Light characteristics of the LED curing unit were determined using spectroradiometer and integrating sphere. Data were analyzed using ANOVA and Tukey’s test (α = 0.05).

Results

At 1 mm, the LED delivered 657.31 mW of power and 908.57 mW/cm² of irradiance; at 10 mm, the values were 326.25 mW and 450.95 mW/cm². Radiant exposure increased with time and was significantly higher at 1 mm (p < 0.01). Longer exposure improved DC, with significant variations among materials (p < 0.01). The highest DC (93 %) was achieved with 1 mm distance after 30 s. Temperature rise also varied by material and increased with irradiance and time (p < 0.01).

Conclusions

Gingival barrier polymerization is influenced by material type, curing distance, and exposure time. Most materials reached adequate conversion with 10 s at 1 mm. However, prolonged curing (30 s) led to temperature increases above 50 °C in some materials. At 10 mm, at least 20 s was required for safe and effective polymerization.

Significance

Gingival barriers should be light-cured for a minimum of 10 s at 1 mm. At 10 mm, exposure time should be extended to at least 20 s to ensure sufficient polymerization while minimizing thermal risk.

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在办公室牙齿漂白中使用的牙龈屏障的最佳光激活时间和热行为

目的评价光固化牙龈屏障材料曝光时间和固化距离对其转化度（DC）和温度变化的影响。方法采用576个圆盘形标本进行体外实验，根据牙龈屏障类型（SDI牙龈屏障、DMC Lase Protect、Ultradent OpalDam、PHS Potenza Blocco、FGM Top Dam、DFL Total Blanc Protetor Gengival）、照射时间（3、5、10、15、20、30 s）和固化距离（Valo、标准模式：1 mm [900 mW/cm²]或10 mm [450 mW/cm²]）3个因素分为72组（n = 8）。微拉曼光谱测定DC。在模拟模型上使用t型热电偶评估热变化。利用光谱辐射计和积分球测定了LED固化单元的光特性。数据分析采用方差分析和Tukey检验（α = 0.05）。结果在1 mm范围内，LED输出功率为657.31 mW，辐照度为908.57 mW/cm²；在10 mm处，分别为326.25 mW和450.95 mW/cm²。辐射暴露随着时间的增加而增加，在1 mm (p <；0.01)。较长的曝光时间改善了直流电，不同材料之间存在显著差异(p <；0.01)。30 s后距离为1mm时DC最高，为93%。温升也因材料而异，并随辐照度和时间的增加而增加(p <；0.01)。结论牙龈屏障聚合反应受材料类型、固化距离和暴露时间的影响。大多数材料在1mm处10 s即可达到充分的转化。然而，长时间的固化（30秒）会导致某些材料的温度升高到50°C以上。在10 mm处，至少需要20 s才能安全有效地聚合。重要意义：牙龈屏障应在1mm处光固化至少10秒。在10毫米处，暴露时间应延长至至少20秒，以确保充分聚合，同时尽量减少热风险。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of dentistry 医学-牙科与口腔外科

CiteScore

7.30

自引率

11.40%

发文量

349

审稿时长

35 days

期刊介绍： The Journal of Dentistry has an open access mirror journal The Journal of Dentistry: X, sharing the same aims and scope, editorial team, submission system and rigorous peer review. The Journal of Dentistry is the leading international dental journal within the field of Restorative Dentistry. Placing an emphasis on publishing novel and high-quality research papers, the Journal aims to influence the practice of dentistry at clinician, research, industry and policy-maker level on an international basis. Topics covered include the management of dental disease, periodontology, endodontology, operative dentistry, fixed and removable prosthodontics, dental biomaterials science, long-term clinical trials including epidemiology and oral health, technology transfer of new scientific instrumentation or procedures, as well as clinically relevant oral biology and translational research. The Journal of Dentistry will publish original scientific research papers including short communications. It is also interested in publishing review articles and leaders in themed areas which will be linked to new scientific research. Conference proceedings are also welcome and expressions of interest should be communicated to the Editor.