Evidenced Based Dentistry Spring 2006 Group 4 Kevin Hancock Jess ... Evidenced Based Dentistry...

Evidenced Based DentistryEvidenced Based DentistrySpring 2006Spring 2006

Group 4Group 4Kevin HancockKevin Hancock

Jess HavronJess HavronBayne HeersinkBayne Heersink

Alec HelmsAlec HelmsNathan JohnsonNathan Johnson

Is InvisalignIs Invisalign®® orthodontics better for orthodontics better for

most young adult patients?most young adult patients?

What are the pros and cons of this What are the pros and cons of this method versus conventional method versus conventional

orthodontics?orthodontics?

What is InvisalignWhat is Invisalign®®??

A series of clear A series of clear plastic alignersplastic aligners

Made of thin, see-Made of thin, see-through plastic through plastic

Fit over the buccal, Fit over the buccal, lingual, and lingual, and occlusal surfaces of occlusal surfaces of teethteeth

Photo: Invisalign.com


Bite impressions are Bite impressions are made.made.

3-D computer imaging 3-D computer imaging technology is used to technology is used to transform the bite transform the bite impressions into a impressions into a custom-made series of custom-made series of clear and removable clear and removable aligners.aligners.



Worn for a Worn for a minimum of 20 minimum of 20 hours per day hours per day (removed for (removed for eating, brushing, eating, brushing, and flossing)and flossing)

Aligners changed Aligners changed every two weeksevery two weeks



Each tray moves a Each tray moves a tooth or group of tooth or group of teeth 0.25 – 0.30 teeth 0.25 – 0.30 mm.mm.

Average treatment Average treatment time is time is approximately one approximately one year. year. Photos: Invisalign.com





TreatmentTreatmentPossible to Treat with Possible to Treat with

InvisalignInvisalign®®

Difficult to Treat with Difficult to Treat with InvisalignInvisalign®®

Mildly crowded and malaligned Mildly crowded and malaligned problems (1-5mm) problems (1-5mm)

Crowding and spacing over 5 mm Crowding and spacing over 5 mm

Spacing problems (1-5mm) Spacing problems (1-5mm) Skeletal anterio-posterior Skeletal anterio-posterior discrepancies of more than 2 mm discrepancies of more than 2 mm

Deep overbite problems (Class II, Deep overbite problems (Class II, div. 2 malocclusions) div. 2 malocclusions)

Centric relation and centric Centric relation and centric occlusion discrepancies occlusion discrepancies

Narrow arches that can be Narrow arches that can be expanded without tipping the teeth expanded without tipping the teeth too much too much

Severely rotated teeth (more than Severely rotated teeth (more than 20 degrees) 20 degrees)

Open bites (anterior and posterior) Open bites (anterior and posterior)

Extrusion of teeth Extrusion of teeth

Severely tipped teeth (more than Severely tipped teeth (more than 45 degrees) 45 degrees)

Teeth with short clinical crowns Teeth with short clinical crowns

Arches with multiple missing teeth Arches with multiple missing teeth

Advantages of InvisalignAdvantages of Invisalign®®

Ideal astheticsIdeal asthetics Ease of use for the patientEase of use for the patient Comfort of wearComfort of wear Simplicity of care and better oral Simplicity of care and better oral

hygienehygiene Potential metal allergy reactions Potential metal allergy reactions

associated with conventional fixed associated with conventional fixed appliances are avoidedappliances are avoided

Advantages (continued)Advantages (continued)

Elimination of treatment options in detail Elimination of treatment options in detail before beginning treatmentbefore beginning treatment

Evaluation of treatment options in detail Evaluation of treatment options in detail before beginning treatmentbefore beginning treatment

The virtual treatment model can serve as The virtual treatment model can serve as a motivation tool for the patienta motivation tool for the patient

Disadvantages of InvisalignDisadvantages of Invisalign®®

Limited control over movementLimited control over movement Limited intermaxillary correctionLimited intermaxillary correction Lack of operator controlLack of operator control Additional time and documentation Additional time and documentation

required if changes have to be made required if changes have to be made once the treatment has startedonce the treatment has started

Slight intrusion (.25-.5 mm) of Slight intrusion (.25-.5 mm) of posterior teeth may occurposterior teeth may occur

Study of 54 InvisalignStudy of 54 Invisalign®® patients after 3-6 patients after 3-6 months treatment (12 questions)months treatment (12 questions)

78% female78% female 44% ages 20-3044% ages 20-30 35% no pain; 54% mild pain (lasting 2-3 35% no pain; 54% mild pain (lasting 2-3

days after placement of new aligner)days after placement of new aligner) 93% said it did not alter normal speech 93% said it did not alter normal speech

patternspatterns 0% reported TMJ pain0% reported TMJ pain 89% were satisfied with treatment89% were satisfied with treatment


Systematic Review of available Systematic Review of available literatureliterature

PurposePurpose– ““To determine the magnitude of the To determine the magnitude of the

reported treatment effects of Invisalignreported treatment effects of Invisalign®®””– ““To help determine which To help determine which InvisalignInvisalign®®

treatment indications are supported by treatment indications are supported by the evidence”the evidence”


Computerized search of online Computerized search of online databases (PubMed, Medline, etc.)databases (PubMed, Medline, etc.)

11stst Search: “Invisalign Search: “Invisalign”” 22ndnd Search: “Invisalign treatment effects” Search: “Invisalign treatment effects”

“ “Humans”Humans”

“ “Clinical Trials”Clinical Trials”

1st Study1st Study

Vlaskalic and BoydVlaskalic and Boyd 38 patients38 patients Placed into three groups depending on Placed into three groups depending on

severityseverity Treatment times (20-32 months)Treatment times (20-32 months) Percentage of patients completing Percentage of patients completing

treatment: 61.5 – 90%treatment: 61.5 – 90%

22ndnd Study Study

Bollen and colleaguesBollen and colleagues ““Evaluating the effect of activation time and Evaluating the effect of activation time and

material stiffness in the ability to complete use material stiffness in the ability to complete use of a first set of prescribed aligners”of a first set of prescribed aligners”

51 subjects51 subjects Randomization into four groupsRandomization into four groups Conclusions: 15 patients completed study (71% Conclusions: 15 patients completed study (71%

dropout rate!); two week activation, simple dropout rate!); two week activation, simple cases, no extractions, low PAR index score cases, no extractions, low PAR index score (more likely to complete initial set of aligners)(more likely to complete initial set of aligners)

ConclusionsConclusions

Both studies had flawsBoth studies had flaws 11stst Study: small sample size; not randomized, Study: small sample size; not randomized,

no specific parameters concerning crowding, no specific parameters concerning crowding, etc.etc.

22ndnd Study: small sample size, large dropout Study: small sample size, large dropout rate, didn’t follow patients through complete rate, didn’t follow patients through complete treatmenttreatment

Therefore, no strong conclusions could be made Therefore, no strong conclusions could be made about Invisalign’s indications or limitationsabout Invisalign’s indications or limitations

Need better and additional clinical trialsNeed better and additional clinical trials


Outcome assessment of InvisalignOutcome assessment of Invisalign®® and traditional and traditional orthodontic treatment compared with the American orthodontic treatment compared with the American

Board of Orthodontics objective grading systemBoard of Orthodontics objective grading system

A retrospective records analysis of non-extraction A retrospective records analysis of non-extraction patientspatients

2 groups, each with 48 patients who were, at the 2 groups, each with 48 patients who were, at the time the study began, the first patients the time the study began, the first patients the orthodontist had completed treatment with orthodontist had completed treatment with InvisalignInvisalign®®, and his other patients he had completed , and his other patients he had completed treatment simultaneously with fixed orthodonticstreatment simultaneously with fixed orthodontics

Patients had treatment with one system or the otherPatients had treatment with one system or the other The groups were controlled for case complexityThe groups were controlled for case complexity

PretreatmentPretreatment

Patients were evaluated using the Discrepancy Patients were evaluated using the Discrepancy Index (DI) to classify patients according to levels Index (DI) to classify patients according to levels of malocclusionof malocclusion

DI consists of 10 categories- overjet, overbite, DI consists of 10 categories- overjet, overbite, anterior open bite, lateral open bite, crowding, anterior open bite, lateral open bite, crowding, occlusion, lingual posterior crossbite, buccal occlusion, lingual posterior crossbite, buccal posterior crossbite, cephalometrics, and “other”posterior crossbite, cephalometrics, and “other”

This allowed the case complexities to be This allowed the case complexities to be controlled in the studycontrolled in the study

Post treatmentPost treatment

Each group was measured for 8 different Each group was measured for 8 different categories using the ABO’s objective categories using the ABO’s objective grading system (OGS) to determine if grading system (OGS) to determine if satisfactory treatment outcome was satisfactory treatment outcome was achievedachieved

Categories are alignment, marginal ridges, Categories are alignment, marginal ridges, buccolingual inclination, occlusal contacts, buccolingual inclination, occlusal contacts, occlusal relations, overjet, interproximal occlusal relations, overjet, interproximal contacts, and root angulationscontacts, and root angulations

Statistical tests used in the studyStatistical tests used in the study

Power test- to determine how many patients in each group Power test- to determine how many patients in each group would yield a study with statistical weightwould yield a study with statistical weight

Chi-square tests- to determine any differences in Chi-square tests- to determine any differences in distribution between the two groups with regard to distribution between the two groups with regard to pretreatment malocclusion and post-treatment resultspretreatment malocclusion and post-treatment results

Also used Wilcoxon-2 sample tests and Spearman Also used Wilcoxon-2 sample tests and Spearman correlation tests to determine if any significant differences correlation tests to determine if any significant differences were present between individual DI and OGS categories were present between individual DI and OGS categories between the two groups, and used to examine differences between the two groups, and used to examine differences in treatment timein treatment time

A P-value of 0.05 was used as the level of statistical A P-value of 0.05 was used as the level of statistical significancesignificance

Results of the studyResults of the study

While the difference in ages of the patients in the two groups was While the difference in ages of the patients in the two groups was statistically significant, the mean DI scores (for pre-treatment statistically significant, the mean DI scores (for pre-treatment evaluation of the cases) were not significant (P=0.9066)evaluation of the cases) were not significant (P=0.9066)

This suggests the two groups were evenly matched in terms of This suggests the two groups were evenly matched in terms of difficulty of the casesdifficulty of the cases

The OGS scores (for post-treatment evaluation) were statistically The OGS scores (for post-treatment evaluation) were statistically significant (P<0.0001)significant (P<0.0001)

4 categories had the greatest discrepancies- buccolingual 4 categories had the greatest discrepancies- buccolingual inclination, occlusal contacts, occlusal relationships, and overjetinclination, occlusal contacts, occlusal relationships, and overjet

Only 10 InvisalignOnly 10 Invisalign®® cases received passing grades, while the fixed cases received passing grades, while the fixed orthodontics group received 23 passing gradesorthodontics group received 23 passing grades

InvisalignInvisalign®® patients had a shorter treatment duration than the patients had a shorter treatment duration than the fixed orthodontics group (1.4 years versus 1.7 years) fixed orthodontics group (1.4 years versus 1.7 years)

DiscussionDiscussion Differences in ages between the two groups is mostly Differences in ages between the two groups is mostly

due to Invisalign’s contraindication for use on persons due to Invisalign’s contraindication for use on persons with non-erupted teeth with non-erupted teeth

Tooth movement in patients should still be similar, Tooth movement in patients should still be similar, regardless of age, and most of the patients in both regardless of age, and most of the patients in both groups were adults who were finished growinggroups were adults who were finished growing

Mean DI scores were similar in each category for both Mean DI scores were similar in each category for both groups, meaning that pre-treatment occlusions for groups, meaning that pre-treatment occlusions for both groups were similar, and thus statistically both groups were similar, and thus statistically insignificantinsignificant

Treatment time may be a factor, because even though Treatment time may be a factor, because even though InvisalignInvisalign®® can produce faster results, the occlusion can produce faster results, the occlusion may not be as idealmay not be as ideal

ConclusionsConclusions

InvisalignInvisalign®® did not score as well on did not score as well on the Objective Grading System as did the Objective Grading System as did fixed orthodontics, and was deficient fixed orthodontics, and was deficient in the categories of occlusal in the categories of occlusal contacts, posterior torque, and contacts, posterior torque, and especially anterior-posterior especially anterior-posterior discrepanciesdiscrepancies

Study limitationsStudy limitations Because the InvisalignBecause the Invisalign®® patients were the first 48 the patients were the first 48 the

orthodontist completed treatment, patients who did orthodontist completed treatment, patients who did not complete Invisalignnot complete Invisalign®® treatment were not included treatment were not included in the study, nor were patients with extractionsin the study, nor were patients with extractions

Since the 48 InvisalignSince the 48 Invisalign®® patients were the first the patients were the first the orthodontist ever treated using the Invisalignorthodontist ever treated using the Invisalign®® system, the operator’s skill is a factor; with time the system, the operator’s skill is a factor; with time the operator’s technique will improveoperator’s technique will improve

To be truly fair, the 48 InvisalignTo be truly fair, the 48 Invisalign®® cases should be cases should be compared to the operator’s first 48 fixed orthodontics compared to the operator’s first 48 fixed orthodontics patients in order to downplay the effect of operator patients in order to downplay the effect of operator skill on the resultsskill on the results

So…So…





Before Invisalign® After Invisalign®

ReferencesReferences Journal of Orofacial Orthopedics, Urban and Vogel, Band Journal of Orofacial Orthopedics, Urban and Vogel, Band

66, Number 2, March 2005, pages 162-173.66, Number 2, March 2005, pages 162-173.

Lagravere, Manuel C., and Carlos Flores-Mir. Lagravere, Manuel C., and Carlos Flores-Mir. "The "The Treatment Effects of Invisalign Orthodontic Treatment Effects of Invisalign Orthodontic Aligners: a Systematic Review." Aligners: a Systematic Review." JADAJADA 136 136 (2005): 1724-(2005): 1724-1729. 1729. PubMedPubMed. Lister Hill . Lister Hill Library, Birmingham, AL.Library, Birmingham, AL.

Djeu, G., Shelton, C., Maganzini, A. “Outcome Djeu, G., Shelton, C., Maganzini, A. “Outcome assessment of Invisalign and traditional assessment of Invisalign and traditional orthodontic orthodontic treatment compared with the treatment compared with the American Board of American Board of Orthodontics objective Orthodontics objective grading system.” grading system.” AJODO AJODO 128 (2005): 292-298. 128 (2005): 292-298. Pubmed. Lister Hill Library, Pubmed. Lister Hill Library, Birmingham, AL.Birmingham, AL.

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