Chewing Efficiency Test in Subjects with Clear Aligners

Masticatory function between chewing with and without wearing clear thermoplastic appliances

BACKGROUND

Clear thermoplastic materials are used in a variety of oral appliances. In some situations, patients may wear clear thermoplastic appliances while eating. However, the effect of wearing clear thermoplastic appliances on chewing efficiency is unknown. This study aimed to evaluate the differences in masticatory function between chewing with and without wearing clear thermoplastic retainers over a 6-month period, and its associated factors.

METHODS

Thirty patients who received upper and lower clear retainers after debonding fixed appliances were examined for objective and subjective masticatory function at retainer delivery (T0), 3-month (T1), and 6-month follow-ups (T2) in two conditions: with and without wearing their retainers while chewing. The objective method used multiple sieves reported as the median particle size (MPS). The food intake ability (FIA) test served as the subjective method. Paired t-test was used to compare the outcomes between chewing with and without retainers at each evaluation time point. Repeated measures ANOVA followed by the Bonferroni post-hoc test was used to compare the outcomes between the three evaluating time points. Multivariable linear regression analysis was performed to assess whether age, sex, and extraction/non-extraction was associated with these effects.

RESULTS

The MPS was significantly greater when chewing with retainers compared with chewing without them at T0 (P < 0.05), however, it was not significantly greater at T1 and T2 (P > 0.05). The MPS with and without the retainers tend to decrease between T0, T1 and T2. In particular, the MPS while chewing with retainers significantly decreased between T0 and T1. The total FIA score and FIA subscores for hard and soft food were significantly lower when eating with retainers at T0 (P < 0.05), however, all FIA scores when eating without retainers did not significantly change between T0, T1, and T2. No significantly associated factors were identified.

CONCLUSIONS

Wearing clear retainers while chewing decreases objective and subjective masticatory function immediately after completing orthodontic treatment. However, this significantly improved to levels comparable to chewing without retainers after a 3-month follow-up. Age, sex, and extraction/non-extraction treatment were not associated with the difference in masticatory function while chewing with and without wearing the retainers.

Assessment of Food Masticatory Capability with Clear Aligners

Nowadays, aligners represent a possible therapeutical approach that combines both esthetic and function in order to address dental malocclusion. However, they require a significant level of compliance from the patient. According to the manufacturer, at least 22 h of wearing a day is demanded to reach the optimal therapeutical level; hence, aligners can only be removed during meals. Patients' compliance might increase and the duration of the treatment might decrease if they were allowed to eat with aligners on. The idea of patients keeping the aligners on during meals has been contemplated, not only to favor patients' compliance but also treatment effectiveness. This study aims to assess the degree of chewing difficulty that aligners cause when eating certain kinds of food and the quantity of residue left.

MATERIAL AND METHODS

A questionnaire titled "Questionnaire for the Assessment of Masticatory Function with Aligners" was administered using Google Forms to 240 patients in treatment with clear aligners. The survey was validated through the reliability test using the test-retest method. This method had a higher correlation coefficient of 0.9 across all items (with a cutoff of 0.8) with statistical significance, and an excellent internal correlation coefficient (α > 0.9). The statistical analysis performed consisted of descriptive analysis, frequencies, percentages, Pearson's correlation test and Friedman's test.

RESULTS

Pearson's test showed a statistically significant correlation between all items except between meat or clams and yogurt or ice cream and with mozzarella or soft cheese regarding food chewing difficulties. Pearson's test showed a statistically significant correlation between all items regarding food residues. A total of 69.2% of the cohort reported some movements of aligners during mastication. In total, 88.3% of them affirmed not to have perceived deformations or breakage of aligners during chewing. Furthermore, 79.2% of them declared that they would continue to eat if eating with aligners was proven to speed up treatment.

CONCLUSIONS

Wearing clear aligners while chewing foods such as yogurt, ice cream, soft cheese, bread, rice, etc., can be possible and can help shorten the duration of orthodontic treatment, benefiting both the patient and the orthodontist. However, further research using qualitative methods is needed to understand the barriers and facilitators to chewing food with aligners.

Chewing Function with Efficiency Tests in Subjects Wearing Clear Aligners

This study assessed the masticatory function of participants wearing clear aligners in order to determine whether these devices can be worn even when eating and therefore worn to extend treatment time and boost treatment effectiveness. An intercontrol test was conducted on 20 patients who received Invisalign® treatment. Each participant was instructed to chew two pieces of Hue-Check Gum® chewing gum (one pink and the other blue) in 5, 10, and 20 cycles both with and without aligners. After being removed from the oral cavity, the gum was dried and pressed using a 1 × 50 × 50 mm model that was 3D printed with a transparent layer in between. After being scanned on both sides with a flatbed scanner at 600 dpi, the samples were saved as jpg files and subjected to an optoelectronic examination using ViewGum software. To validate the procedure, a control group from a different institution (University of Bern) was used. A statistical analysis of the data was carried out. The Shapiro-Wilk test was used to confirm the normality of the samples. A one-way ANOVA test, a homogeneity of variance test, and a t-test did not reveal statistically significant differences between the two control groups, thus validating the methodology employed. In summary, clear aligners do not radically change the masticatory function while they are worn. As a result, clinicians can exploit the aligners for chewing to obtain a better fit of the plastic material to the dental surface and to attachments. Treatment times for patients could also be shorter.

An evaluation of the Invisalign® Aligner Technique and consideration of the force system: a systematic review

OBJECTIVE

Since its introduction 25 years ago, the Invisalign® system has undergone multiple digital and biomechanical evolutions and its effectiveness is often compared to traditional systems without considering the many differences which characterize them. The main aim of this systematic review is to look at the literature dealing with studies on teeth movements using the Invisalign® system and the management of these movements through digital planning and artificial intelligence.

MATERIALS AND METHODS

The following electronic databases were searched: MEDLINE, Embase, the Cochrane Oral Health Group's Trials Register, and CENTRAL. Unpublished studies were searched on ClinicalTrials.gov, the National Research Register, and Pro-Quest Dissertation Abstracts and Thesis database.

RESULTS

Twenty-four studies (15 retrospective, 5 prospective, 2 pilot, and 2 case-control) were included. The results of the analysis carried out on the available literature show that the Invisalign® system is recognized to be a valid alternative to conventional orthodontic treatment in no-extraction cases. The results are influenced by the methods for assessing the effectiveness of this technique and by the comparison bias of the traditional system with the innovative digital system.

CONCLUSIONS

Since the introduction of SmartForce and SmartTrack material, the efficacy of the treatment has improved. There is still a shortage of high-quality evidence concerning the treatment modality. In order to make the treatment with the aligners more efficient, a correct management of the ClinCheck® software and a proper use of the biomechanics are necessary. The aligned force-driven system should be taken into account when developing the digital planning.

Risk factors and prevention of choking

Choking (or foreign body airway obstruction) is a widespread phenomenon with serious consequences of morbidity and mortality. Choking (often also called suffocation) can be caused by food or inedible objects and leads to various degrees of asphyxiation or lack of oxygen in the blood stream. The incidence is very high in both young children and adults, especially seniors. However, since not all choking episodes end up in the emergency room or become fatalities, they often escape statistics. Although episodes of choking from non-edible bodies are infrequent, they affect mostly young children. Three of the most common risks for choking in general are neurological disorders, dysphagia and dental issues (few or no teeth, unstable or unsuitable prosthesis or orthodontic appliances).  The purpose of this study was to evaluate the risk factors of choking and ways to reduce/avoid this event. We reported data on a series of 138 patients admitted to the emergency department following a choking event, at a hospital in Rome, Italy. The age group of the analyzed population ranged from 1 to 88 years, with the most represented age group of these between 40 and 59, with a similar distribution between males and females. The types of foods on which people choked reflected the seasonal, traditional and local foods: 67% of patients reported choking on fish bones followed by meat bones (9%)  and artichokes (3%). Three relevant non-food choking elements reported were: orthodontic items, toothpicks and pins (one occurrence each). We also reported on two clinical cases of patients choking on meat and a chicken bone. In conclusion, choking awareness and prevention are essential for implementing potential life-saving precautions. Prevention is the first tool to reduce the occurrence of this event, therefore it is necessary to analyze the risk factors and educate the population to eliminate them. Proper chewing and oral manipulation are paramount functions in preventing choking, along with meal-time supervision if little children and elderly. Then, it behooves the healthcare professionals to disseminate knowledge.