Influence of mandibular and palatal intraoral appliances on erosion in situ study outcome

Abstract

The standardization of in situ protocols for dental erosion is important to enable comparison between studies. Objective: Thus, the objectives of this study were to evaluate the influence of the location of in situ intraoral appliance (mandibular X palatal) on the extent of enamel loss induced by erosive challenges and to evaluate the comfort of the appliances. Material and Methods: One hundred and sixty bovine enamel blocks were selected according to their initial surface hardness and randomly divided into two groups: GI - palatal appliance and GII - mandibular appliance. Twenty volunteers wore simultaneously one palatal appliance (containing 4 enamel blocks) and two mandibular appliances (each one containing 2 enamel blocks). Four times per day during 5 days, the volunteers immersed their appliances in 0.01 M hydrochloric acid for 2 minutes, washed and reinserted them into the oral cavity for 2 hours until the next erosive challenge. After the end of the in situ phase, the volunteers answered a questionnaire regarding the comfort of the appliances. The loss of tissue in the enamel blocks was determined profilometrically. Data were statistically analyzed by paired t-test, Chi-square and Fisher's Exact Test (p<0.05). Results: The enamel blocks allocated in palatal appliances (GI) presented significantly higher erosive wear when compared to the blocks fixed in mandibular appliances (GII). The volunteers reported more comfort when using the palatal appliance. Conclusions: Therefore, the palatal appliance is more comfortable and resulted in higher enamel loss compared to the mandibular one.

Eroded enamel rehardening using two intraoral appliances designs in different times of salivary exposure

“…Thus, it was expected that the enamel samples in the mandibular appliances, supposedly under greater influence of the parotid gland, could be benefited with increased salivary flow and subsequent remineralization. However, this study showed no difference in enamel remineralization degree using upper palatal and lower buccal appliances, therefore the re-hardening effect of saliva from different sites might not be the responsible for the less enamel loss resulted from the use of mandibular appliance in previous studies (6,7).…”

“…Santos et al (6) investigated the effect of the period of use and location of intraoral appliances on enamel surface loss and have concluded that the intermittent use of appliances resulted in similar enamel loss compared to the continuous use. When considering all the erosive cycling process (erosive demineralization and rehardening), the enamel blocks located on the maxillary appliance presented significantly higher erosive enamel loss when compared to the enamel blocks of the mandibular appliance (6,7). On the other hand, when considering only one event of erosive demineralization there was no difference on the enamel hardness using the maxillary and mandibular appliances by volunteers (12) Another result showed no difference for the re-hardening effect after a single erosive demineralization (11), however is important to emphasize that in this last study the mandibular appliance was made with soft silicon plate, covering the entire lower arch, presenting a completely different design of the appliance used in the present study.…”

“…Important scientific data regarding preventive measures for erosion comes from in situ models (6,7). The main advantage of the in situ models is the closely resembling of the natural environment due to the presence of salivary flow and acquired pellicle formation (8).…”

“…Our research group have been studied different types of in situ appliances with a variety of time use, in order to find a protocol that better simulates a patient at risk of developing dental erosion (6,7,11-13). Santos et al (6) investigated the effect of the period of use and location of intraoral appliances on enamel surface loss and have concluded that the intermittent use of appliances resulted in similar enamel loss compared to the continuous use.…”

Biomimetic Effect of Nano-Hydroxyapatite in Demineralized Enamel before Orthodontic Bonding of Brackets and Attachments: Visual, Adhesion Strength, and Hardness in In Vitro Tests

“…During orthodontic treatment, the presence of the appliance can influence periodontal parameters [5] and raise the risk of dental erosion [6]. e management of dental enamel involves both correct oral hygiene practices and the application of remineralizing products, based on calcium, phosphates, and fluorides [7].…”