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Color fading of the blue compliance indicator encapsulated in removable clear Invisalign Teen (R) aligners

March 2011
The Angle Orthodontist 81(2):185-91

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PubMed

Authors:

To evaluate the color fading in aqueous solutions of the blue dot wear-compliance indicators of the Invisalign Teen® System outside the oral cavity. The compliance indicators in the Invisalign Teen aligners were tested for color resistance in various aqueous models with no saliva involved. Color fading was observed as a function of time, pH, and temperature while compliance indicators were stored in drinking water or sour soft drinks and in conjunction with the use of cleaning tablets and a dishwasher. The findings of color fading were consistent with the color changes observed when the aligners were being worn by patients. Color fading, notably as observed in connection with acidic soft drinks and cleaning techniques, introduces uncertainty into the assessment of actual patient compliance, as reflected by the fading colors of compliance indicators. Compliance indicators are not immune to simple intentional or unintentional manipulations. Therefore, they can best show an estimate of wear time but cannot be recommended as objective wear-time indicators.

(a) Removable Invisalign Teen H Aligner equipped with two dark blue compliance indicators. (b) Site of aligners with enclosed ‘‘fast’’ compliance indicators. The color intensity of the blue compliance indicator is shown in 1b before treatment (dark blue), in 2b during treatment (light blue), and in 3b after treatment (clear) of the aligner in the aqueous environment (see Table 1).

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Original Article

Color fading of the blue compliance indicator encapsulated in removable

clear Invisalign TeenHaligners

Timm Cornelius Schott

; Gernot Go¨ z

ABSTRACT

Objective: To evaluate the color fading in aqueous solutions of the blue dot wear-compliance

indicators of the Invisalign TeenHSystem outside the oral cavity.

Materials and Methods: The compliance indicators in the Invisalign Teen aligners were tested for

color resistance in various aqueous models with no saliva involved.

Results: Color fading was observed as a function of time, pH, and temperature while compliance

indicators were stored in drinking water or sour soft drinks and in conjunction with the use of cleaning

tablets and a dishwasher. The findings of color fading were consistent with the color changes

observed when the aligners were being worn by patients. Color fading, notably as observed in

connection with acidic soft drinks and cleaning techniques, introduces uncertainty into the

assessment of actual patient compliance, as reflected by the fading colors of compliance indicators.

Conclusion: Compliance indicators are not immune to simple intentional or unintentional

manipulations. Therefore, they can best show an estimate of wear time but cannot be

recommended as objective wear-time indicators. (Angle Orthod. 2011;81:185–191.)

KEY WORDS: Removable aligners; InvisalignHTeen; Compliance indicator; Encapsulated dye

INTRODUCTION

Compliance is a mandatory for effective treatment

with a removable orthodontic appliance.

1,2

Studies of

self-reported wear times as compared to the results of

clinical assessment have shown that reliable informa-

tion was obtained in only 43% of patients.

A total of

140 patients with a mean age of 12.7 years were

surveyed by questionnaire.

The majority expressed a

desire to wear their appliances only at night, and they

did not wish to have wear times prescribed. When

patients were informed that their headgear wear times

were being recorded, they did tend to wear the

headgear more regularly but still fell short of the actual

instructions given.

Align Technology recently started distributing a

compliance indicator that was designed for use on

young patients treated with the InvisalignHTeen sys-

tem.

According to the manufacturer, the compliance

indicator uses the food dye Erioglaucine disodium salt,

which is encapsulated in the clear Invisalign Teen

aligner and is released from the polymer in the pre-

sence of oral fluid.

The amount of dye loss will

correspond with the amount of time the aligner was

worn in the oral cavity. Two different blue dot wear

indicators (fast and slow fading) are used to ensure

that individual patients’ different saliva compositions

are appropriately accounted for. The different color

fading is based on the different amount of the diffused

dye determined by the pore sizes of the polymer. The

blue dots are embedded in the vestibular part of the

molar segments of the aligners (Figure 1). Wear time

is determined by assessing the way in which the

compliance indicators change color as the aligner is

worn. The clinician is required to evaluate five potential

color changes (ranging from dark blue/dark blue to

clear/clear) to obtain a graphic representation of the

wear time.

In a study of 14 patients who were prescribed

Invisalign TeenHwith clear aligners and embedded

color indicators, it was concluded that the service times

determined from the compliance indicators showed

good agreement with the number of service hours

reported by the patients. The positive assessment of

compliance based on compliance indicators, however,

Resident, Department of Orthodontics, Eberhard Karl Uni-

versity, Tu¨bingen, Germany.

Professor and Department Chair, Department of Orthodon-

tics, Eberhard Karl University, Tu¨ bingen, Germany.

Corresponding author: Dr Timm Cornelius Schott, Depart-

ment of Orthodontics, Eberhard Karl University, Osianderstr. 2-

8, 72076 Tu¨bingen, Germany

(e-mail: timm_schott@gmx.de; timm.schott@med.uni-tuebingen.

de)

Accepted: August 2010. Submitted: May 2010.

G2011 by The EH Angle Education and Research Foundation,

Inc.

DOI: 10.2319/052610-288.1 185 Angle Orthodontist, Vol 81, No 2, 2011

rested on very different color changes observed in

individual patients against a background of similar

wearing patterns. Following the initial wear time of

2 weeks, the compliance indicators revealed that, of the

nine patient examples listed, four patients showed a

clear/clear pattern, four patients showed a clear/blue

pattern, and one patient showed a blue/blue pattern,

although all patients were expected to have worn the

aligners for 20 to 22 hours in a 24-hour period. The

theoretical possibility that patients included in the study

may have attempted to manipulate the compliance

indicator system was consciously ruled out.

Given the widely diverging color changes, it remains

unclear whether the variance in the values obtained

may have been caused by different wear times as a

result of lack of patient compliance or whether any

unknown factors may have exerted an influence on the

fading of the embedded dye. These considerations

prompted us to investigate factors that might have

contributed to the color changes.

MATERIALS AND METHODS

Seven Invisalign TeenHaligners (A) were obtained

directly from the manufacturer (Align Technology Inc,

Santa Clara, Calif). Fourteen Invisalign TeenHaligners

(B) were provided by an orthodontic office that

routinely uses the InvisalignHsystem.

The light-dependent color stability of the food dye

Erioglaucine disodium salt (also known as Alphazur-

Figure 1. (a) Removable Invisalign TeenHAligner equipped with two dark blue compliance indicators. (b) Site of aligners with enclosed ‘‘fast’’

compliance indicators. The color intensity of the blue compliance indicator is shown in 1b before treatment (dark blue), in 2b during treatment

(light blue), and in 3b after treatment (clear) of the aligner in the aqueous environment (see Table 1).

186 SCHOTT, GO

¨Z

Angle Orthodontist, Vol 81, No 2, 2011

ine FG, FD&C Blue 1, Brilliant Blue FCF, or Acid

Blue 9), which was obtained from Sigma-Aldrich

Chemie (Munich, Germany), was proven by irradia-

tion with an ultraviolet lamp (254 nm) for 2 weeks.

The color stability of the dissolved dye was tested by

dissolving a spatula tip of solid Erioglaucine in

250 mL of drinking water, resulting in a dark blue

solution. The pH-, time-, and temperature-dependent

color stability of this blue solution was proven in a

range of pH 2–9 by adding 1 N HCl or 1 N NaOH

and keeping it in these solutions for 2 weeks at 20uC

or 35uC.

The oxidation-dependent color fading of the blue dye

solution was tested by adding Kukident cleaning

tablets (Reckitt Benckiser, Mannheim, Germany) to

the solution and storing it at 20uC or 35uC. Among

other chemicals, these tablets contain an oxidant com-

pound in the form of sodium carbonate peroxide.

The color fading of the compliance indicator was

investigated by storing the Invisalign TeenHaligners

in 250 mL drinking water at 20uC, 35uC, and 50uC

as well as in different aqueous solutions at 20uC

and 35uC. The first solution studied was created by

adding a Kukident cleaning tablet to 250 mL drinking

water. Commercially available soft drinks and a fruit

juice were used for the remaining solutions: Coca-

Cola (Berlin, Germany), Schweppes Original Bitter

Lemon (Schweppes, Kreuztal, Germany), and lemon

juice (Hitchcock Sportfit Fruchtsaft, Rheinberg,

Germany). Aligners were stored in 250 mL of each

aqueous medium.

RESULTS

Color Stability of Food Dye Erioglaucine

Disodium Salt

The Erioglaucine disodium salt that was used as the

compliance indicator was light resistant in its solid and

nonembedded form. The pH-dependent color stability

of the food dye can be postulated, because a deep

blue aqueous solution of the dye in the range of pH 2–

9 retained its color throughout the 2 weeks. This

finding was also obtained when lemon concentrate

(20% by vol) was added, regardless of whether the

solution was kept at 20uC or 35uC over the 2-week

period. In contrast, the blue aqueous solution lost its

color entirely within 24 hours of adding a Kukident

cleaning tablet and maintaining the solution at 35uC,

while storage at 20uC delayed the process of complete

color loss by a few days (Table 1). The loss of color of

the dye was presumably a result of oxidative degra-

dation in the wake of peroxide formation triggered by

the Kukident tablet dissolving in water.

Color Fading of the Compliance Indicator in

Different Aqueous Solutions

The pH-, time-, and temperature-dependent fading

patterns of the embedded compliance indicator were

determined. To this end, the aligners were stored in

drinking water and only in various common highly

acidic soft drinks (but not including saliva), as the

aligners under study embedded the dye in the form

of a stable sodium salt. Acidic soft drinks were

therefore more likely to destabilize the dye; in neutral

or slightly alkaline beverages, the sodium salt form of

the dye was more likely to be preserved. Alcoholic

beverages were not included. Testing was carried

out for a maximum of 2 weeks, as the aligners

included in the Invisalign TeenHsystem were rou-

tinely replaced within 2 or 3 weeks over the course of

treatment. The aligners were stored in various liquids

at both room temperature (,20uC) and/or at 35uC.

The latter temperature was used to simulate thermal

conditions present in the oral cavity: ranges of

33.10uC–37.80uC

and 35uC–36uC

have been re-

ported. Temperature-dependent color fading was

additionally evaluated by storing the aligners in

drinking water at 50uC, since temperatures may

reach peaks of 58.8uC in the anterior segment and

54uC in the premolar area (notably when drinking hot

beverages).

A wide variety of cleaning procedures

have been used on removable appliances (eg,

Kukident cleaning tablets, mechanical cleaning, or

application of vinegar).

Kukident cleaning tablets

and cleaning in a dishwasher were included in the

present study of color changes in aligners. Aligners

obtained from two different sources (A 5obtained

directly from the manufacturer; B 5provided by an

orthodontic office) were used to determine whether

the dye was encapsulated with sufficient reproduc-

ibility during manufacturing to yield consistently

reproducible color changes in aligners. In addition,

parallel testing was conducted with aligners from the

same patients (B1/B2).

Color Fading After Storage in Water

The instructions for use provided by the manufac-

turer suggested that the embedded dye would fully

retain its blue color until exposed to moisture and

temperatures equal to or higher than body tempera-

ture. However, we observed that the compliance

indicators of two aligners belonging to different

sources would change their ‘‘fast’’ and ‘‘slow’’ color

formulation from dark to light blue when stored in

drinking water, even at approximately 20uC, which is

considerably below body temperature (see Table 1).

Corresponding fading of the compliance indicators was

found in patients taking part in the 12-week study after

COLOR FADING OF INVISALIGN TEENHALIGNERS 187

Angle Orthodontist, Vol 81, No 2, 2011

Table 1. Color Fading of the Blue Compliance Indicators After Soaking of Unused Aligners (A) in 250 mL of Different Aqueous Media at

Different Temperatures, pH, and Time in Comparison to the Color Change of the Compliance Indicators of 50 Aligners After Use by Patients for

17–22/24 Hours Over 14 Days (B)

188 SCHOTT, GO

¨Z

Angle Orthodontist, Vol 81, No 2, 2011

they had worn the aligners for 17.5 to 23 hours in a

24-hour period.

The initial dark blue of the ‘‘fast’’ formulation faded

completely when the aligner A was stored in water at

35uC over 13 days, while the dark blue color of the

‘‘slow’’ formulation changed to light blue under the

same conditions. The same pattern was observed on

graphical analysis of 22 of 50 compliance indicators in

patients who had each worn a total of six aligners for

2 weeks each. At 50uC, the dark blue color of both

compliance indicators of a used aligner faded to clear

after only 7 days.

Color Fading After Storage in Water with One

Kukident Tablet

Color fading was fast when a Kukident cleaning

tablet was added to the drinking water holding the

aligner. In this environment, both color formulations

(‘‘fast’’ and ‘‘slow’’) included in the compliance indica-

tors of aligner A changed from dark blue to clear within

13 days. Under the same conditions, the color of the

other aligner (B) changed from dark to light blue. When

the same experiment was conducted at 35uC, the

‘‘fast’’ color formulation in aligner A took 24 hours to

fade, and both formulations faded within 4 days. The

aligner B showed a clear/light blue pattern of fading

after 5 days, which faded to clear/clear after 9 days.

When the experiment was repeated with aligners B1

and B2, these changed to light blue/clear within 4.5

and 5.5 days, respectively. Complete fading was noted

after 7 days with aligner B1 and after 9 days with

aligner B2. Complete fading of both formulations was

also observed with the compliance indicators in 13 of

50 aligners of different patients worn for 2 weeks for

the prescribed wearing time, while the same pattern

was not observed in the remaining 37 aligners.

Color Alterations on Storage in Acidic Soft Drinks

Color changes were also observed when the

aligners were stored in Coca-Cola, a very popular

drink and one of the most acidic (pH 2.6)

soft drinks

available. At ,20uC, the dark blue color of the new

aligners (A) changed to clear (fast formulation) or light

blue (slow formulation) within 13 days, while the worn

aligners (B) acquired a light blue/light blue color during

the same period of time. Again, the fading pattern

obtained with Coca-Cola would have suggested good

patient compliance, even though the aligners had

never been worn. At 35uC, both formulations resulted

in a light blue/light blue pattern within 2 weeks.

Presumably, this weak change was caused by more

escaping from the Coca-Cola solution at 35uC

than at 20uC, such that the initially low pH value would

rise toward a pH of 7 as the reaction proceeded.

Marked changes were also observed when the

compliance indicators were stored in Schweppes

Original Bitter Lemon (pH 2.5). When the aligners B

were stored at roughly 20uC, one of both formulations

of the indicator completely lost its color, while the other

formulation turned light blue. Strikingly, aligner B1 took

7 days to achieve this color change, while aligner B2

took 9 days. The fading was complete for both

compliance indicators by that time and did not

progress any further when the aligners were stored

in Schweppes for up to 2 weeks. Similar fading

patterns were observed at 35uC. Much as with Coca-

Cola as the medium, the fact that different tempera-

tures did not cause a difference in fading patterns was

presumably a result of CO

escaping at higher

temperatures, raising the pH and reducing the acidic

effect of the Schweppes medium. This assumption

was supported by the storage of the aligners in lemon

juice (pH ,2.3). At 20uC, the initially dark blue color of

both indicators changed to light blue within 2 weeks. At

35uC, by contrast, the compliance indicators complete-

ly lost their color in 9 days. This pronounced effect of

temperature was not observed with Coca-Cola and

Schweppes as media and was presumably a result of

the noncarbonated nature of the lemon juice. In other

words, the acidic pH of the lemon juice (,2.3)

remained unchanged at 35uC or even decreased

slightly, whereas the acid content of acidic soft drinks

increased slightly at higher temperatures.

Color Alterations After Cleaning in a Dishwasher

Color fading was also observed when the aligners

were subjected to dishwashing. After two program

cycles in the dishwasher (roughly 5 hours), including

the use of a commercially available detergent and

temperatures of up to 50uC, the compliance indicators

changed from dark blue to light blue.

DISCUSSION

This investigation adds to the existing series of reports

dealing with the InvisalignHsystem.

12–14

Interindividual

differences in color change patterns had, in the past,

been attributed to different compositions of saliva. Since

the dark blue color remained unchanged when the food

dye was stored in nonencapsulated form in aqueous

media within the same temperature (20uC/35uC) and pH

(2–9) ranges, the observed fading of the compliance

indicators was not caused by instability of the dye. The

reason for the different fading patterns among aligners

was presumably caused by the manufacturing of

different encapsulations of the dye, with each pair

consisting of a ‘‘fast’’ and a ‘‘slow’’ compliance indicator.

The encapsulations of the ‘‘fast’’ and ‘‘slow’’ formulations

were located on alternating sides of the aligners. It was

COLOR FADING OF INVISALIGN TEENHALIGNERS 189

Angle Orthodontist, Vol 81, No 2, 2011

not possible to determine the locations of the ‘‘fast’’ vs

‘‘slow’’ formulations on the aligners.

Once the aligner was exposed to aqueous medium,

the way in which the blue dye physically diffused from

the encapsulation in a time-, pH-, and temperature-

dependent fashion would result in a gradual change

from dark blue to clear. The addition of Kukident

cleaning tablets presumably induced not only diffusion

but also chemical reactions that gave rise to colorless

metabolites of the encapsulated dye.

Therefore, our experiments indicate that the wide

variation of color changes noted between aligners

despite similar wear times

are not caused solely by

individual differences in the composition of saliva (as

postulated by the manufacturer) but also by effects

demonstrated in the present study for the first time.

The finding that the compliance indicators of Invisalign

Teen taken from the same source and tested in

identical experimental setups (eg, drinking water plus

Kukident cleaning tablet at 35uC) failed to show

identical fading patterns would suffice to account for

the large variances in fading that can occur even in

patients who strictly adhered to the prescribed wear

times. Another possible source of error is in the very

technique of determining wear times based on the

fading patterns of compliance indicators, as it requires

the investigator to rate the color changes on a five-

point scale. Because of its inherent subjectivity, this

method does not yield objective wear times. Based on

experience and on the precision of fit presented by the

aligners, the orthodontist can judge their patients’

compliance even without the use of compliance

indicators.

It would appear that patients could easily manipu-

late the color indicators, either on purpose or

unintentionally. Clinicians should remember this

possibility whenever, for instance, an aligner does

not fit, even though the color indicators would seem

to suggest an adequate level of patient compliance.

One should also bear in mind that undesirable color

changes may be present because the patient forgot

to remove the aligner from the mouth during drinking.

Situations in which aligners no longer fit during

treatment, requiring extensive new treatment plan-

ning despite the fact that the indicators of the aligners

have completely or partially faded, will constitute a

dilemma. Clinicians will have to assume in this

situation that the aligners have been worn by the

patient as instructed, and this is also what the

patients themselves (or their parents) may think.

Based on current thinking, the finding of color

indicators having duly faded would effectively rule

out that patient compliance was lacking. Consequent-

ly, this factor would no longer be suspected in the

event of treatment failure, but the focus of suspicion

might well shift to the Invisalign Teen system or the

clinician’s skills.

CONCLUSIONS

NThe compliance indicator encapsulated in the clear

Invisalign Teen aligners was released in different

aqueous solutions in the absence of oral fluid outside

the oral cavity.

NColor changes deviating from the graphically deter-

mined baseline throughout the treatment period with

removable aligners could be caused by the following

reasons: the aligners were left in the mouth during

drinking, were kept in water, were cleaned with

tablets containing oxidizing agents, or were cleaned

in a dishwasher.

NThe fading pattern of the compliance indicators is not

suitable as an objective measure of wear time.

ACKNOWLEDGMENTS

We would like to thank Dr T. Drechsler (private practice,

Wiesbaden, Germany) and Align Technology Inc for kindly

providing the Invisalign Teen aligners used in these experi-

ments. The study was supported by the Fortu¨ ne Program

(project no. 1850-0-0).

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Jan 2023

Wearable technology to augment traditional approaches are increasingly being added to the arsenals of treatment providers. Wearable technology generally refers to electronic systems, devices, or sensors that are usually worn on or are in close proximity to the human body. Wearables may be stand-alone or integrated into materials that are worn on the body. What sets medical wearables apart from other systems is their ability to collect, store, and relay information regarding an individual’s current body status to other devices operating on compatible networks in naturalistic settings. The last decade has witnessed a steady increase in the use of wearables specific to the orofacial region. Applications range from supplementing diagnosis, tracking treatment progress, monitoring patient compliance, and better understanding the jaw’s functional and parafunctional activities. Orofacial wearable devices may be unimodal or incorporate multiple sensing modalities. The objective data collected continuously, in real time, in naturalistic settings using these orofacial wearables provide opportunities to formulate accurate and personalized treatment strategies. In the not-too-distant future, it is anticipated that information about an individual’s current oral health status may provide patient-centric personalized care to prevent, diagnose, and treat oral diseases, with wearables playing a key role. In this review, we examine the progress achieved, summarize applications of orthodontic relevance and examine the future potential of orofacial wearables.

Factors Influencing Patient Compliance during Clear Aligner Therapy: A Retrospective Cohort Study

Article

Full-text available

Jul 2021

Compliance is highly relevant during clear aligner therapy (CAT). In this retrospective cohort study, we assessed compliance and associated covariates in a large cohort of CAT patients. A comprehensive sample of 2644 patients (75.0% females, 25.0% males, age range 18–64 years, median 27 years), all receiving CAT with PlusDental (Berlin, Germany) finished in 2019, was analyzed. Covariates included demographic ones (age, gender) as well as self-reported questionnaire-obtained ones (satisfaction with ones’ smile prior treatment, the experience of previous orthodontic therapy). The primary outcome was compliance: Based on patients’ consistent use of the mobile application for self-report and aligner wear time of ≥22 h, patients were classified as fully compliant, fairly compliant, or poorly compliant. Chi-square test was used to compare compliance in different subgroups. A total of 953/2644 (36.0%) of patients showed full compliance, 1012/2644 (38.3%) fair compliance, and 679/2644 (25.7%) poor compliance. Males were significantly more compliant than females (p = 0.000014), as were patients without previous orthodontic treatment (p = 0.023). Age and self-perceived satisfaction with ones’ smile prior to treatment were not sufficiently associated with compliance (p > 0.05). Our findings could be used to guide practitioners towards limitedly compliant individuals, allowing early intervention.

Is the use of clear aligners a real critical change in oral health prevention and treatment?

Article

Full-text available

Mar 2021

Gabriella Galluccio

The introduction, in the late years of the last century, of clear aligners therapy (CAT) has drastically changed the approach' perspective to orthodontic treatment. Both patients and clinicians' expectations appear to be addressed with clear aligner therapy achieving an aesthetic appearance and fewer side effects, mainly due to the difficult maintenance of proper oral hygiene in the conventional fixed approach. Research has partially confirmed these key points of CAT but similarly revealed several limitations to the overall benefit of this treatment. Both the aforementioned key points of the CAT are currently under discussion: the aesthetic appearance is not uniform, due to the presence in some cases of extensive need for attachments, and the better periodontal conditions are certainly present in the CAT but mainly limited to the short term. This critical review of the state of the art clarifies the gray areas, such as to inform the researcher with the aim of elaborating an adequate study design in order to evaluate the advantages and limitations of this orthodontic approach.

The Effect of High-Frequency Vibration on Tooth Movement and Alveolar Bone in Non-Growing Skeletal Class II High Angle Orthodontic Patients: Case Series

Article

Full-text available

Oct 2020

Tarek El-Bialy

This study presents a novel technique utilizing high-frequency vibration to shorten treatment time and preserve alveolar bone in challenging orthodontic cases that have been treated with Invisalign® clear aligners. Four non-growing orthodontic patients (age range 14-47 years old) with Class II skeletal patterns (convex profiles with retrognathic mandibles) who sought correction of their crowded teeth and non-surgical correction of their convex profiles were included in this study. These patients were treated using Invisalign clear aligners together with high-frequency vibration (HFV) devices (120 Hz) (VPro5™) that were used by all patients for five minutes per day during active orthodontic treatment. Vertical control and forward rotation of the mandible for each patient was achieved through pre-programming the Invisalign to produce posterior teeth intrusion. Successful forward rotation of the mandibles achieved in all patients led to improvement of their facial convex profiles (apical base relationship (ANB) improved 2.1 ± 0.5 degrees; FMA (Frankfurt mandibular plane angle) improved 1.2 + 1.1 degrees). Dental decompensation was achieved by lingual tipping of the lower incisors and palatal root torque of upper incisors. The use of HFV together with Invisalign facilitated achieving these results within a 12 ± 6 months period. In addition, more bone labial to the lower incisors after their lingual movement was noted. In conclusion, the use of HFV concurrent with SmartTrack Invisalign aligners allowed complex tooth movement and forward mandibular projection without surgery in non-growing patients with skeletal Class II relationships. The clinical impact and implications of this case series are: (1) the use of HFV facilitates complex orthodontic tooth movement including posterior teeth intrusion and incisor decompensation; (2) forward mandibular projection of the mandible and increased bone formation labial to lower incisors can be achieved in non-growing patients that may minimize the need for surgical intervention in similar cases or gum recession due to lower incisors labial inclination.

What every general dentist needs to know about clear aligners

Article

Jul 2020
Gen Dent

In recent years, the demand for esthetic orthodontic treatment options for adult patients has increased dramatically. Clear aligner therapy (CAT) has become a popular method of orthodontic therapy that now allows for comprehensive treatment with more complex dental movements. Moreover, the increasing role of technology in dental treatments has made CAT more appealing to providers and patients. The aim of this article is to highlight the clinical scope and limitations of CAT and to outline the differences among various clear aligner products.

Integrating skeletal anchorage into fixed and aligner biomechanics

Article

Jun 2022

Routine alignment with fixed appliances and aligners is indeterminate mechanics because equilibrium equations are only applicable to two abutments: teeth, segments, or arches. Orthodontists must depend on compliance and resilience of materials (archwires and aligners) for initial alignment. However, stabilized segments and arches are "large multirooted teeth" that can be moved with determinate mechanics using temporary skeletal anchorage devices. Temporary skeletal anchorage devices have advanced from retromolar implants and inter-radicular miniscrews to extra-alveolar bone screws placed in the basilar bone buccal to the first molars: mandibular buccal shelf and infrazygomatic crest. Extra-alveolar anchorage is determinate mechanics to move teeth, segments, and arches. Retraction and rotation of the lower arch reverses the etiology of Class III open bite malocclusion to correct severe skeletal dysplasia with no extractions or orthognathic surgery.

Effectiveness of a compliance indicator for clear aligners

Article

Full-text available

May 2009
J Clin Orthod

Intra-oral temperature variation over 24 hours

Article

Full-text available

Jul 1999

This study aimed to investigate temperature variation at archwire sites adjacent to the maxillary right central incisor and first premolar, its correlation with ambient temperature, and the influence of inter-racial variation. Twenty young adult male subjects were randomly selected (13 Asian, seven Caucasian). Thermocouples were attached to the labial archwire component of custom-made orthodontic retainers at the two intra-oral sites. A third thermocouple measured ambient temperature. A data-logger recorded temperatures at 5-second intervals over a 24-hour period. Temperatures ranged from 5.6 to 58.5 degrees C at the incisor and from 7.9 to 54 degrees C at the premolar, with medians of 34.9 degrees C and 35.6 degrees C, respectively. Ambient temperature correlated poorly with the intra-oral temperatures. The Asian and Caucasian groups had significantly different temperature distributions. On average during the 24-hour period, temperatures at the incisor site were in the range of 33-37 degrees C for 79 per cent of the time, below it for 20 per cent, and above it for only 1 per cent of the time. Corresponding figures for the premolar site were 92, 6, and 2 per cent. At both archwire sites the most frequent temperatures were in the range of 35-36 degrees C. The data presented demonstrate that the temperature at sites on an archwire in situ varies considerably over a 24-hour period and that racial differences may exist. This information should be considered during the manufacture and use of temperature-sensitive orthodontic materials, in particular nickel-titanium archwires and springs.

Die kieferorthopädische Behandlung aus Patienten- und Elternsicht-Ergebnisse einer Fragebogenstudie in Praxis und Klinik - Teil II

Article

Nov 1990

Im Rahmen einer umfangreichen Fragebogenstudie an ber 300 funktionskieferorthopdisch behandelten Patienten und ihren Eltern wurden die Zufriedenheit mit Behandlungsmitteln sowie Arzt-Patient-Interaktion und die Einschtzung des eigenen Trageverhaltens untersucht. Bei der berwiegenden Mehrheit der Befragten lie sich eine positive oder indifferente Haltung zur Behandlung erkennen. Differenzierungs-und Kritikfhigkeit nehmen mit dem Lebensalter zu. Sprechbeeintrchtigungen stellen den meistgenannten Kritikpunkt dar; psychosoziale Nachteile durch das Tragen der Apparatur werden vor allem von den Eltern vermutet. Eine Minderheit der Patienten fhlt sich vom Kieferorthopden nicht entsprechend ihren sozial-emotionalen Bedrfnissen und Erwartungen behandelt. Abstriche vom verlangten Soll werden besonders beim vor- und nachmittglichen Tragen der Apparatur eingerumt. Die fr den Befolgungsgrad mitentscheidende elterliche Kontrolle erfolgt entweder mit Engagement und Anteilnahme oder in eher formal-ritualisierter Weise oder bleibt insgesamt unzureichend, und zwar in jeweils etwa einem Drittel der Flle.A questionnaire investigation enrolling more than 300 orthodontic patients and their parents was conducted into the subjective appraisal of treatment means and doctor-patient-interaction. The majority of the interviewees showed a positive respectively indifferent attitude toward their treatment. As patients grow older, their views become more differentiated and critical. Impaired speaking was mentioned most frequently; psychosocial disadvantages caused by appliance wear were suggested mostly by parents. In a minor part of patients, the orthodontist's behavior was not in line with their social-emotional needs and expectations. Slight failures of adherence with prescriptions were admitted for the daytime. Parental supervision appeared to be either energetic or formal yet superficial, or insufficient respectively in one third of our cases.

Young Patients’ Attitudes toward Removable Appliance Wear Times, Wear-time Instructions and Electronic Wear-time Measurements – Results of a Questionnaire Study

Article

Mar 2010
J OROFAC ORTHOP

To determine the attitude of young patients to removable appliance wear times, wear-time instructions and electronic wear-time measurement. 140 patients (mean age 11.97 years) undergoing orthodontic treatment with removable appliances expressed their wishes about wear times and wear-time instructions in a questionnaire. The questionnaires were analyzed by means of descriptive statistical analysis. Analysis of this questionnaire investigation according to gender revealed that the majority of the respondents preferred wearing their appliances overnight only, and that they did not want their practitioners determining the length of the appliance wear. We observed gender-specific differences in the acceptance of wear times as determined by the dental practitioner, which were accepted by 58% of the girls but only 28% of the boys. Willingness to wear a removable appliance increased markedly when the orthodontic objectives included offering patients the prospect of an improvement in their appearance from wearing a removable appliance. A recently-developed removable appliance with an integrated microsensor on the market that provides an objective measure of appliance wear times would only be worn without reservations by about 21% of boys and 32% of girls. 41-45% of the respondents only agreed to treatment using this kind of microsensor provided the treatment period would be thereby shortened. The extent to which the clinician can respond to the wishes and requirements of young patients in terms of removable appliance wear is crucial to the compliance necessary for success. Acceptance of a removable appliance with an integrated electronic wear-time recorder can be enhanced if the practitioner explains to the patient in a simple, straightforward manner the therapeutic advantage of this new generation of appliances. Society's growing openness towards electronic devices does not yet appear to be reflected in the desire of young patients for braces with an integrated microsensor.

Comparative Use of Invisalign (R) by Orthodontists and General Practitioners

Article

May 2010

To test the hypothesis that there is no difference in the use of Invisalign between orthodontists and general practitioners. Materials and A questionnaire was mailed to all Invisalign providers within a 35-mile radius of Stony Brook University. The answers were statistically analyzed. The level of significance was set at P < .05. Orthodontists started more Invisalign cases (P < .0001). General practitioners started more Invisalign cases in the last 12 months (P = .0012). For both groups, the percentage of cases started in the last 12 months was inversely related to the number of years certified in Invisalign (P < .0001). Significant differences in opinion (P < .001) were noted between orthodontists and general practitioners regarding the level of experience necessary to treat a Class I malocclusion with a large diastema, and whether a Class II subdivision case should be treated with Invisalign. The hypothesis is rejected. The use of Invisalign by orthodontists and general practitioners was compared, and significant differences were found.

How well does Invisalign work? A prospective clinical study evaluating the efficacy of tooth movement with Invisalign

Article

Feb 2009

The purpose of this prospective clinical study was to evaluate the efficacy of tooth movement with removable polyurethane aligners (Invisalign, Align Technology, Santa Clara, Calif). The study sample included 37 patients treated with Anterior Invisalign. Four hundred one anterior teeth (198 maxillary and 203 mandibular) were measured on the virtual Treat models. The virtual model of the predicted tooth position was superimposed over the virtual model of the achieved tooth position, created from the posttreatment impression, and the 2 models were superimposed over their stationary posterior teeth by using ToothMeasure, Invisalign's proprietary superimposition software. The amount of tooth movement predicted was compared with the amount achieved after treatment. The types of movements studied were expansion, constriction, intrusion, extrusion, mesiodistal tip, labiolingual tip, and rotation. The mean accuracy of tooth movement with Invisalign was 41%. The most accurate movement was lingual constriction (47.1%), and the least accurate movement was extrusion (29.6%)- specifically, extrusion of the maxillary (18.3%) and mandibular (24.5%) central incisors, followed by mesiodistal tipping of the mandibular canines (26.9%). The accuracy of canine rotation was significantly lower than that of all other teeth, with the exception of the maxillary lateral incisors. At rotational movements greater than 15 degrees, the accuracy of rotation for the maxillary canines fell significantly. Lingual crown tip was significantly more accurate than labial crown tip, particularly for the maxillary incisors. There was no statistical difference in accuracy between maxillary and mandibular teeth of the same tooth type for any movements studied. We still have much to learn regarding the biomechanics and efficacy of the Invisalign system. A better understanding of Invisalign's ability to move teeth might help the clinician select suitable patients for treatment, guide the proper sequencing of movement, and reduce the need for case refinement.

[Orthodontic treatment from the patients' and parents' viewpoint--the results of a practical and clinical questionnaire study (II)]

Article

Jan 1991

A questionnaire investigation enrolling more than 300 orthodontic patients and their parents was conducted into the subjective appraisal of treatment means and doctor-patient-interaction. The majority of the interviewees showed a positive respectively indifferent attitude toward their treatment. As patients grow older, their views become more differentiated and critical. Impaired speaking was mentioned most frequently; psychosocial disadvantages caused by appliance wear were suggested mostly by parents. In a minor part of patients, the orthodontist's behavior was not in line with their social-emotional needs and expectations. Slight failures of adherence with prescriptions were admitted for the daytime. Parental supervision appeared to be either energetic or formal yet superficial, or insufficient respectively in one third of our cases.

The Role of Diet in the Aetiology of Dental Erosion

Article

Feb 2004

Acids of intrinsic and extrinsic origin are thought to be the main etiologic factors for dental erosion. There is evidence that acidic foodstuffs and beverages play a role in the development of erosion. However, the pH of a dietary substance alone is not predictive of its potential to cause erosion as other factors modify the erosive process. These factors are chemical (pKa values, adhesion and chelating properties, calcium, phosphate and fluoride content), behavioural (eating and drinking habits, life style, excessive consumption of acids) and biological (flow rate, buffering capacity, composition of saliva, pellicle formation, tooth composition, dental and soft tissue anatomy). The interplay between erosion and abrasion (specially oral hygiene practices) may be the main driver leading to the clinical manifestation of this disorder. Recommendations for patients at risk for dental erosion such as reducing acid exposure by reducing the frequency and contact of acids will be discussed.

The relationship between enamel softening and erosion caused by soft drinks at a range of temperatures

Article

Apr 2006
J DENT

Investigations of the erosive potential of soft drinks are usually performed at room or body temperature, but drinks are more frequently served chilled, with ice, or hot. Since the rate of chemical reactions usually increases with temperature, it is predicted that erosion is more severe at high temperatures and reduced at low temperatures. The aim of this study was to investigate the correlation between enamel softening, enamel erosion, and temperature. Atomic force microscopy nanoindentation and non-contact optical profilometry were used to assess changes in enamel nanomechanical properties after 5 min and erosive material loss after 30 min exposure to two different non-carbonated soft drinks at 4, 25, 50 and 75 degrees C. For one drink (Robinson's Original Juice Drink), there was a statistically significant difference between nanomechanical properties and erosion depth at all temperatures, with softening and erosion increasing with temperature. For another drink (Ribena ToothKind Juice Drink), there was a slight softening and virtually no material loss, and temperature had no statistically significant impact on erosion. There was a good linear correlation (R2 = 0.94) between nanomechanical properties and material loss. The difference between the drinks can be explained by their composition. For the erosive drink, material loss increased, and nanohardness decreased, approximately linearly with temperature. The correlation between softening and erosion demonstrated that nanomechanical properties after very short erosion times can be considered a good predictor of bulk material loss after considerably longer erosion times.

Clinical and quantitative assessment of headgear compliance: A pilot study

Article

Mar 2006

This study was undertaken to evaluate the compliance of patients using headgear with a timing device and to determine the efficiency of the electronic module timer as a patient motivator. Twenty-one patients (average age, 14 years 10 months) were selected from the orthodontic clinic of Federal University of Paraná on the basis of headgear wear for anchorage. The patients were instructed to wear their headgear 14 hours a day for a given number of days. The headgears were equipped with recorders (Compliance Science System and Affirm smart headgear modules, Ortho Kinetics, Vista, Calif). The patients were not told about the recorders, but they were instructed to keep track of their wear times. At the end of the test period (T1), the patients' reported wear times were compared with readings from the electronic modules. The patients were assigned a second period of headgear wear (T2) and told that their use would be monitored electronically. Again, the wear times reported by the patients were compared with the values from the electronic modules. Total time, number of hours accumulated between sessions, and quality time (uninterrupted use of headgear) were assessed. Patients reported wearing their headgear an average of 13.6 hours per day; the electronic modules detected 5.6 hours per day in T1 and 6.7 hours per day in T2. Quality time was 1.8 hours per day in T1 and T2. The mean actual hours of daily wear relative to the provider's requirement was 56.7% in T1 and 62.7% in T2. Boys were more compliant than girls. After they learned of the electronic device, the girls' compliance improved. Younger patients were more compliant than older ones. The compliance rate of older patients improved slightly in T2. Patients tend to overreport their headgear wear times. The mean actual hours of daily wear relative to the providers' requirement was 56.7%. This increased to 62.7% when patients knew a recording device was being used. A monitoring system can provide feedback to the patient, facilitate parental involvement, and motivate patients to comply with headgear wear.