Effects of Chlorhexidine and Fluoride on Irradiated Enamel and Dentin

Abstract

The effectiveness of mouthwash protocols in preventing gamma irradiation therapy damage to the ultimate tensile strength (UTS) of enamel and dentin is unknown. It was hypothesized that the use of chlorhexidine and fluoride mouthwash would maintain the UTS of dental structures. One hundred and twenty teeth were divided into 2 groups: irradiated (subjected to 60 Gy of gamma irradiation in daily increments of 2 Gy) and non-irradiated. They were then subdivided into 2 mouthwash protocols used 3 times per day: 0.12% chlorhexidine, 0.05% sodium fluoride, and control group (n = 10). The specimens were evaluated by microtensile testing. The results of the Tukey test (p < 0.05) indicated that the gamma irradiation therapy significantly reduced the UTS of the enamel, crown, and root dentin. Macromolecular alterations were suggested by optical retardation data in dentin. Structural alterations, in both substrates, were detected by scanning electron microscopy analysis. Mouthwash with 0.12% chlorhexidine partially prevented the damage to the mechanical properties of the irradiated crown dentin, whereas the 0.05% sodium-fluoride-irradiated enamel showed UTS similar to that of non-irradiated enamel.

Effect of Gamma Radiation on Mechanical Properties of Tooth Structure

“…Additionally, in the current study, the samples were placed in artificial saliva during irradiation to simulate, as precisely as possible, the conditions that are found in the oral cavity [16] . However, other media, including 0.9% saline solution [6,13] , distilled water [11,15] , or buffered phosphate solution [11] , have been used to store teeth in similar studies. Although artificial saliva does not exactly mimic the characteristics of natural saliva, especially in the case of patients undergoing head and neck radiation therapy, who present changes in the flow, secretion, and composition of natural saliva [22] , artificial saliva is still considered the most suitable storage medium [16,23] .Studies of the structural changes in enamel and dentin following irradiation are controversial [6,[11][12][13]15,16] .…”

“…The conflicting results that have been observed are most likely due to the lack of standardization of the methodology in the various studies assessing the direct radiogenic damage to the enamel and dentin. These investigations have used dental substrates of either bovine origin [11][12][13] or human origin [6,7,15,16] , which have been subjected to different doses of radiation [14] and different methods of radiation, mostly with fractional irradiation and some without [12,24] . The novel findings of the present investigation demonstrates that ionizing radiation led to a dose-dependent increase in the enamel micro hardness, and a cumulative dose of 60 Gy yielded the highest micro hardness values.…”

“…Scientific evidence indicates that patients incur a lifelong risk of developing radiation caries following radiation therapy [7] .The effects of radiation therapy on the onset and progression of a caries lesion might be direct or indirect [8] .The indirect effects of irradiation include changes in the quality and quantity of saliva, difficulty in performing proper oral hygiene, increased intake of cariogenic foods,and changes in the oral microbiota [5,7,9] . Radiation therapy may also exert direct effects on the dental structure,including changes in the crystalline structure, enamel and dentin microhardness, dentinoenamel junction, and acid solubility of the enamel; these effects might be involved in the pathogenesis of the disease [6,[10][11][12][13][14][15][16] . The direct effects of radiation on the deciduous dentitionare still unknown because studies addressing this issue have only been conducted in bovine teeth and in human permanent teeth.…”

Effect of high energy X-ray irradiation on the nano-mechanical properties of human enamel and dentine

“…4,5 Irradiation of the enamel and dentine of the teeth can influence their nano-mechanical structure by decreasing their ultimate tensile Declaration of Interests: The authors certify that they have no commercial or associative interest that represents a conflict of interest in connection with the manuscript. strength 6,7 and fracture resistance; this is also true of restored teeth 8 . Irradiation also adversely affects the bonding of resin-based composites to enamel and dentine, causing damage to restored teeth.…”

Effect of Gamma Radiation and Endodontic Treatment on Mechanical Properties of Human and Bovine Root Dentin

“…However, ionizing radiation generally causes damage to healthy tissues adjacent to the radiation sites (1). Radiotherapy can modify substantially the mechanical strength of human enamel and dentin, producing more deleterious effects on the protein components than on the mineralized portion of dentin (2)(3)(4)(5). Severe damage resultant from gamma radiation on the organic components of dentin, like collagen matrix, odontoblastic processes and pulp complex, should be considered in patients under head and neck oncologic treatment (6).…”