A comparison of treatment impacts between Invisalign aligner and fixed appliance therapy during the first week of treatment

Invisalign, an innovative invisible orthodontic appliance to correct malocclusions: advantages and limitations

Tooth movement may be achieved by the use of sequential positioners made by altering tooth positions on set-up models to simulate progress of treatment. The principle is based upon Kesling's positioner concept of 1945, though its subsequent application to splint therapy was labour intensive and did not result in precise tooth movement. Invisalign was developed by Align Technology, Inc (Santa Clara, CA, USA) in 1997 by applying 3-D imaging technology to overcome these problems, and permitting customization on a large scale. Their system offers significant advantages, but still suffers from limitations which are discussed in this article.

The effect of chewing gum on the impact, pain and breakages associated with fixed orthodontic appliances: a randomized clinical trial

OBJECTIVES

To determine whether the use of chewing gum reduced the impact and pain of fixed orthodontic appliances.

SETTING AND SAMPLE POPULATION

The Orthodontic Department of the Charles Clifford Dental Hospital, Sheffield, UK. Fifty-seven patients aged 18 years or younger and who were about to start fixed orthodontic appliance treatment.

SUBJECTS AND METHODS

A randomized clinical trial with two parallel groups either allocated to receive chewing gum after placement of their appliance or who were asked not to chew gum. The patients completed a previously validated Impact of Fixed Appliances questionnaire at 24 h and 1 week following each visit up until the placement of the working archwire. A visual analogue scale (VAS) was used to assess the intensity of pain. Appliance breakages were recorded to the end of treatment.

RESULTS

The difference between the median Total Impact Score of the two groups at 24 h was 16, which was significant (p = 0.031; Mann-Whitney U-test). The difference between the median VAS between the two groups at 24 h was 25 mm, which was significant (p = 0.038; Mann-Whitney U-test). There were no differences at 1 week. None of the risk ratios for appliance breakages were significant.

CONCLUSION

Chewing gum significantly decreased both the impact and pain from the fixed appliances. There was no evidence that chewing gum increased the incidence of appliance breakages.

Preparation and characterization of thermoplastic materials for invisible orthodontics

PETG/PC/TPU polymer blend was prepared by mechanical blending. The mechanical properties of modified PETG/PC/TPU blend were characterized using a universal testing machine, and results were compared against two commercial thermoplastic products -Erkodur and Biolon. Blending modification improved the properties of PETG/PC/TPU. When blending ratio (wt%) was 70/10/20, PETG/PC/TPU exhibited optimal mechanical properties which exceeded those of Erkodur and Biolon. Tear strength was 50.23 MPa and elongation at break was 155.99%. Stress relaxation rate was 0.0136 N/s after 1 hour, which was significantly slower than Erkodur and Biolon (p<0.05). Water absorption rate was 0.57% after 2 weeks, which was significantly lower than Erkodur and Biolon (p<0.05).

Comparison of oral impacts experienced by patients treated with labial or customized lingual fixed orthodontic appliances

INTRODUCTION

Our objective was to compare the oral impacts experienced by patients treated with labial or customized lingual fixed orthodontic appliances.

METHODS

This was an age- and sex-matched prospective longitudinal study of 60 adult patients treated with either labial or customized lingual fixed orthodontic appliances over a 3-month period. Ratings of oral impacts experienced and satisfaction were made on visual analog scales at 3 time points after appliance fixation. Variations in oral impacts and satisfaction over the trajectory of treatment were assessed. Area-under-the-curve analyses were conducted to assess variations in oral impacts and satisfaction between the groups.

RESULTS

All patients experienced oral impact disturbances, although these disturbances decreased over time (P < 0.001). Patients treated with customized lingual appliances reported more oral discomfort (P < 0.001), dietary changes (P < 0.001), swallowing difficulty (P < 0.001), speech disturbances (P < 0.001), and social problems (P < 0.001) than did those in the other group. There was no significant difference between the groups regarding ratings of oral self-care, mastication, and satisfaction level of treatment (P > 0.05).

CONCLUSIONS

The findings indicate that oral impacts are commonly experienced during both labial and customized lingual fixed orthodontic therapies. However, the oral impacts decreased over the observational period. Patients treated with customized lingual appliances experienced more oral impacts. Both groups had similar levels of treatment satisfaction.

Adult patients' adjustability to orthodontic appliances. Part I: a comparison between Labial, Lingual, and Invisalign™

This prospective study examined the adult patient's perception of recovery after insertion of three types of orthodontic appliances: Buccal, Lingual and Invisalign. The sample consisted of sixty-eight adult patients (45 females and 23 males) who comprised three groups: 28 Buccal, 19 Lingual, and 21 Invisalign patients. After appliance insertion, patients completed a Health-Related Quality of Life questionnaire daily for the first week and again on day 14, in order to assess patients' perception of pain and analgesic consumption. In addition, four areas of dysfunction were assessed: oral dysfunction, eating disturbances, general activity parameters, and oral symptoms. Lingual appliance was associated with more severe pain and analgesic consumption, the greatest oral and general dysfunction, and the most difficult and longest recovery. The Invisalign patients complained of relatively high levels of pain in the first days after insertion; however this group was characterized by the lowest level of oral symptoms and by a similar level of general activity disturbances and oral dysfunction compared to the Buccal appliance. Many Lingual and some Buccal patients did not reach a full recovery from their eating difficulties by the end of the study period. The present study provides information to adult patients and clinicians assisting them in choosing the most appropriate treatment modality in relation to Health-Related Quality of Life parameters.

A comparison of pain experienced by patients treated with labial and lingual orthodontic appliances

SUMMARY

The aim of this prospective longitudinal study was to compare pain experiences among Chinese adult patients treated with labial and lingual orthodontic appliances. Sixty patients, 30 with labial appliances (18 females and 12 males, mean age 20.33 years, SD +/- 4.205) and 30 with lingual appliances (22 females and 8 males, mean age 21.63 years, SD +/- 2.236), rated their overall pain experience on a 100 mm visual analogue scale (VAS) at three time points: 1 week (T(1)), 1 month (T(2)), and 3 months (T(3)) after bracket placement. In addition, on a separate 100 mm VAS, they rated their pain experience at the locations of the tongue, lips, cheeks, gums, face, and jaw at T(1), T(2), and T(3). Changes in pain VAS were conducted using Friedman analysis of variance, area under the curve (AUC) analysis and the data were compared using a t-test. There was no significant difference in global ratings of pain among those treated with labial or lingual appliances (P > 0.05). Among both groups, global ratings of pain decreased over the study period (P < 0.001). Patients treated with lingual appliances reported higher ratings of tongue pain (P < 0.001), while those treated with labial appliances reported higher ratings of lip (P < 0.001) and cheek (P < 0.001) pain. The findings indicate that patients treated with labial and lingual appliances rate similarly the level of overall pain they experience during treatment. Ratings of overall pain experienced decreased for both treatment groups with time. However, ratings of pain differed at various sites with respect to the type of orthodontic appliance. These findings have implications in informing patients' treatment decision-making processes regarding labial and lingual appliances and in the management of discomfort associated with different treatment modalities.