Nikos Erotokritou
Fifth Year, Group 15Comparison of periodontal health between patients with
fixed orthodontic appliances and Invisalign®.
A systematic review
Master’s Thesis Supervisor: Assoc. prof. PhD Arūnas Vasiliauskas Kaunas 20182 LITHUANIAN UNIVERSITY OF HEALTH SCIENCES
MEDICAL ACADEMY FACULTY OF ODONTOLOGY
CLINIC OF ORTHODONTICS
Comparison of periodontal health between patients with fixed orthodontic appliances and Invisalign®. A systematic review
Master’s Thesis
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Kaunas, 2018
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EVALUATION TABLE OF THE MASTER’S THESIS
OF THE TYPE OF SYSTEMIC REVIEW OF SCIENTIFIC LITERATURE
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No. MT parts MT evaluation aspects
Compliance with MT requirements and evaluation Yes Partially No 1 Summary (0.5 point)
Is summary informative and in compliance with the
thesis content and requirements? 0.3 0.1 0
2 Are keywords in compliance with the thesis essence? 0.2 0.1 0 3 Introducti
on, aim and tasks
(1 point)
Are the novelty, relevance and significance of the
work justified in the introduction of the thesis? 0.4 0.2 0 4 Are the problem, hypothesis, aim and tasks formed
clearly and properly? 0.4 0.2 0
5 Are the aim and tasks interrelated? 0.2 0.1 0
6 Selection criteria of the studies, search methods and strategy (3.4 points)
Is the protocol of systemic review present? 0.6 0.3 0 7
Were the eligibility criteria of articles for the selected protocol determined (e.g., year, language,
publication condition, etc.)
0.4 0.2 0
8
Are all the information sources (databases with dates of coverage, contact with study authors to identify additional studies) described and is the last search day indicated?
0.2 0.1 0
9
Is the electronic search strategy described in such a way that it could be repeated (year of search, the last search day; keywords and their combinations; number of found and selected articles according to the combinations of keywords)?
0.4 0.1 0
10
Is the selection process of studies (screening, eligibility, included in systemic review or, if applicable, included
in the meta-analysis) described? 0.4 0.2 0
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Is the data extraction method from the articles (types of investigations, participants, interventions, analyzed factors, indexes) described?
0.4 0.2 0
12
Are all the variables (for which data were sought and any assumptions and simplifications made) listed and defined?
0.4 0.2 0
13 Are the methods, which were used to evaluate the
4 information is to be used in data synthesis,
described?
14 Were the principal summary measures (risk ratio,
difference in means) stated? 0.4 0.2 0
15 Systemiza- tion and analysis of data (2.2 points)
Is the number of studies screened: included upon assessment for eligibility and excluded upon giving the reasons in each stage of exclusion presented?
0.6 0.3 0
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Are the characteristics of studies presented in the included articles, according to which the data were extracted (e.g., study size, follow-up period, type of respondents) presented?
0.6 0.3 0
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Are the evaluations of beneficial or harmful outcomes for each study presented? (a) simple summary data for each intervention group; b) effect estimates and confidence intervals)
0.4 0.2 0
18
Are the extracted and systemized data from studies presented in the tables according to individual tasks?
0.6 0.3 0
19
Discussion (1.4 points)
Are the main findings summarized and is their
relevance indicated? 0.4 0.2 0
20 Are the limitations of the performed systemic
review discussed? 0.4 0.2 0
21 Does author present the interpretation of the
results? 0.4 0.2 0
22
Conclusions (0.5 points)
Do the conclusions reflect the topic, aim and tasks
of the Master’s thesis? 0.2 0.1 0
23 Are the conclusions based on the analyzed material?
0.2 0.1 0
24 Are the conclusions clear and laconic? 0.1 0.1 0
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References (1 point)
Is the references list formed according to the
requirements? 0.4 0.2 0
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Are the links of the references to the text correct? Are the literature sources cited correctly and precisely?
0.2 0.1 0
27 Is the scientific level of references suitable for Master’s thesis? 0.2 0.1 0 28
Do the cited sources not older than 10 years old form at least 70% of sources, and the not older than 5 years – at least 40%?
0.2 0.1 0
Additional sections, which may increase the collected number of points
29 Annexes Do the presented annexes help to understand the
analyzed topic? +0.2 +0.1 0
30 Practical
recommen -dations
Are the practical recommendations suggested and
are they related to the received results? +0.4 +0.2 0
31
Were additional methods of data analysis and their results used and described (sensitivity analyses, meta-regression)?
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*Remark: the amount of collected points may exceed 10 points.
Reviewer’s comments: ___________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ _________________________________________ Reviewer’s name and surname
___________________________ Reviewer’s signature
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Was meta-analysis applied? Are the selected statistical methods indicated? Are the results of each meta-analysis presented?
+2 +1 0
General requirements, non-compliance with which reduce the number of points
33
General require-ments
Is the thesis volume sufficient (excluding annexes)?
15-20 pages (-2 points)
<15 pages (-5 points) 34 Is the thesis volume increased artificially? -2 points -1 point
35 Does the thesis structure satisfy the requirements of Master’s thesis? -1 point -2 points 36 Is the thesis written in correct language,
scientifically, logically and laconically? -0.5 point -1 points 37 Are there any grammatical, style or
computer literacy-related mistakes? -2 points -1 points 38 Is text consistent, integral, and are the
volumes of its structural parts balanced? -0.2 point -0.5 points
39 Amount of plagiarism in the thesis. >20%
(not evaluated) 40
Is the content (names of sections and sub- sections and enumeration of pages) in compliance with the thesis structure and aims?
-0.2 point -0.5 points
41
Are the names of the thesis parts in compliance with the text? Are the titles of sections and sub-sections
distinguished logically and correctly?
-0.2 point -0.5 points
42 Are there explanations of the key terms
and abbreviations (if needed)? -0.2 point -0.5 points 43
Is the quality of the thesis typography (quality of printing, visual aids, binding) good?
-0.2 point -0.5 points
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TABLE OF CONTENTS
ABSTRACT
..………..…...…...71. INTRODUCTION
………...……..8-9 1.1 AIM.………...….……….……...9 1.2 TASKS….………..……….…….9 1.3 HYPOTHESIS……….……….…...92. MATERIAL AND METHODS
………...….………..….10-14 2.1 FOCUS QUESTION..………102.2 TYPES OF PUBLICATION..………..………..10
2.3 TYPES OF STUDIES..………..10
2.4 POPULATION.….………...……….10
2.5 DATA COLLECTION.………….………...………...….………10
2.6 LITERATURE SEARCH AND SCREENING..……...………...….11
2.7 SELECTION OF STUDIES.……….11
2.8 INCLUSION AND EXCLUSION CRITERIA ………11
2.9 ASSESSMENT OF BIAS RISK ….………...…………....…13
2.10 ABBREVIATIONS………..……...14
3. RESULTS
………...……….…………...…..….14-19 3.1 STUDY SELECTION……….……143.2 SYSTEMIZATION OF DATA AND CHARACTERISTICS OF STUDIES………...….…15
3.3 EVALUATION OF DATA……….………16
3.4 COMPARISON OF INDICES IN THE CHOSEN STUDIES………...……17
3.5 INDIVIDUALIZATION OF RESULTS FROM EACH STUDY……….……...….17-19
4. DISCUSSION
………...………..…….19-205. CONCLUSION
……….…20-216. PRACTICAL RECOMMENDATIONS.
……….217. REFERENCES
………...……….21-237
Abstract
Introduction:
The purpose of this systematic review was to identify studies in literature that explore the periodontal health of patients with fixed orthodontic appliance and Invisalign® during and after treatment.
Materials and methods:
Databases such as EMBASE, Medscape and PubMed/Medline were electronically searched to retrieve results. Articles included studies on humans, published in English.
Results:
A total of 61 studies were identified through preliminary search. After application of inclusion and exclusion criteria a total of 6 articles were determined to be eligible for this review. A total of 385 patients were enlisted in this systematic review. The plaque index showed significant difference between patients with fixed orthodontic appliances and Invisalign® aligners. The papillary bleeding index, sulcus probing depth and gingival index however showed no statistically difference between the two groups.
Conclusion:
It is concluded from this analysis that patients treated with Invisalign had better periodontal status than the ones treated with fixed orthodontic appliances. However more studies are needed to confirm this conclusion in the future.
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1. Introduction
Orthodontic treatment assures proper alignment of the teeth and enhances the occlusal and jaw relationship. These benefits include improvement of mastication, speech, and facial aesthetics, but also endue general and oral health, ameliorating quality of life. [1] However like any other treatment orthodontic treatment has complications. Periodontal complications are one of the most observed side effects associated with orthodontics. [2] The evolution of medical technology in the recent decades has ensued the improvement in people’s living standard, consequently people are more susceptible to mind the appearance of their periodontal health status. Oral health plays an important role in general health and quality of life. A healthy mouth is free from periodontal disease, tooth decay and other diseases that restraint on a person’s ability to eat, smile and speak.
Thus far, fixed orthodontic treatment remains the best option for the different types of malocclusion and able to produce very precise tooth movement to achieve ideal results. [3] However, this type of treatment has some drawbacks since people wearing traditional braces feel uncomfortable and conscious about their appearance. Moreover, it is difficult to perform conventional cleaning. Patients must carefully brush each bracket and floss around the wires to remove all traces of plaque, in order to reduce the risk of demineralization during orthodontic treatment. [4]
Furthermore, microbiological studies have revealed substantial changes in the bacterial composition of the subgingival dental plaque, indicating that orthodontic treatment is possible to change the equilibrium of oral microflora and increase bacteria accumulation.[5] It has been shown that treatment with fixed orthodontic appliances stimulates the growth of a subgingival plaque where some periodontopathogenic bacterial strains are prevalent, such as Porphyromonas gingivalis, Prevotella
intermedia, Bacteroides forsythus, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, and Treponema denticola.[6-8]
In 1999, a pioneer orthodontic system based on a polymer comprised by a chain of organic units joined with urethane links was introduced (Invisalign®, Align Technology, Santa Clara, California). A thin, transparent plastic that fits over the buccal, lingual/palatal, and occlusal surfaces on the teeth, which was previously computer designed. [9] Invisalign® appliances are removable, therefore patients feel more comfortable aesthetically, than patients with fixed orthodontic appliances. Invisalign® is also not permanently attached to teeth the way traditional braces are, and can be easily removed for cleaning and adequate tooth brushing thus allowing patients to preserve oral hygiene to optimal levels. It’s presented as an alternative for most patients with mild to moderate malocclusion or alignment problem. At present, a lot of scholars believe that patients wearing Invisalign® are more
9 favourable to maintain acceptable periodontal health than patients undergoing treatment with the traditional fixed appliances. However, the Invisalign® system usually requires those patients to spend a minimum of 20 hours per day wearing the Invisalign® and to remove it only during eating, drinking, tooth brushing, or flossing. [10] Because the surfaces of the teeth are fitted over, it is possible to cause periodontal damage due to improper cleaning of the oral cavity.
Evidence that has existed in literatures for decades indicates that individuals with poor oral hygiene, especially during orthodontic treatment have higher rate of gingivitis and periodontal diseases.
1.1 AIM:
The aim of this systematic review was to explore the periodontal health of patients with fixed orthodontic appliance and Invisalign® during and after treatment.
1.2 Tasks:
To compare which treatment option permits a better oral hygiene regime according to the periodontal health indices.
To assess the oral hygiene status during treatment.
To investigate whether the treatment duration has an impact in periodontal health.
1.3 Hypothesis:
The hypothesis of this systematic review is that patients treated with Invisalign® aligners have better oral hygiene and lower values in periodontal indices during evaluation than patients with fixed orthodontic appliances.
10
2. Material and Methods:
2.1 Focus Question
The focus question was developed according to the problem, intervention, comparison, and the outcome study design. (PICO) is presented in Table 1.
Table 1. PICO table.
Population (P) Patients who are during or underwent orthodontic treatment with
Fixed Orthodontic Appliances and Invisalign® Aligners
Intervention (I) Periodontal Status during and after Treatment (Indices)
Comparison (C) Comparison of treatment with Fixed Orthodontic Appliances and
Invisalign® Aligners
Outcome (O) Superior Periodontal Health Status of Invisalign® Aligners than
Fixed Orthodontic Appliances
Focus Question
Does the type of orthodontic treatment modality (Fixed Orthodontic Appliances or Invisalign® Aligners) affect the periodontal status of patients?
2.2 Types of publication
The systematic review included studies on human published in the English language.
2.3 Types of studies
The systematic review included all humans prospective cohort studies and a randomized controlled clinical trial published between 2002-2017, that reported a comparison of the periodontal health of patients during treatment with the Invisalign® System and with Fixed Orthodontic Appliances.
2.4 Population
Patients who are during or underwent orthodontic treatment with fixed orthodontic appliances and Invisalign® aligners.
2.5 Data collection
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2.6 Literature search and screening
To detect the appropriate studies, a thorough electronic search was carried out according to PRISMA guidelines [11] within EMBASE, Medscape and PubMed/Medline databases using different combinations of the following keywords:
"Invisalign" [All Fields] AND "Fixed" [All Fields] AND ("orthodontic appliances"[MeSH Terms] OR ("orthodontic"[All Fields] AND "appliances"[All Fields]) OR "orthodontic appliances"[All Fields]) AND "Periodontal" [All Fields] AND ("health"[MeSH Terms] OR "health"[All Fields]) Also a manual search was performed to find additional relevant articles and references.
2.7 Selection of studies
Searched articles were clarified according to inclusion and exclusion criteria. Primarily titles and abstracts were obtained for all the studies that were considered adequate for inclusion in this systematic review. (Figure 1)
2.8 Inclusion and exclusion criteria
Inclusion criteria for the assortment were:
Randomized controlled trial (RCT) or prospective cohort study which compared the periodontal health status in patients undergoing orthodontic treatment with fixed orthodontic appliances or Invisalign®.
Articles written in English Language Clinical studies performed on humans
Exclusion criteria for the assortment were:
Non-prospective cohort study or non-RCT trial. Review articles. Non-preclinical studies
12 •PubMed/Medline, EMBASE, Medscape
•Search keywords: ‘’Invisalign’’ ,’’Fixed Orthodontic Appliances’’, ’’Periodontal
health’’ •Language: English •Species: Human (n=60) S cre ening Inc luded Eligi bil it y Ide nti fic ati on
Additional records identified through other sources
•Cumhuriyet Dental Journal November 2013
(n = 1 )
Records screened after duplicates removed (n = 60 ) Records screened (n = 60 ) Records excluded: •Non-preclinical Studies •Sponsored studies •Not relevant title and
abstracts (n = 52 ) Full-text articles
assessed for eligibility (n = 8 )
Full-text articles reviewed and excluded: •Limited access (n=1) •Not relevant content (n=1)
Studies included in qualitative synthesis
(n = 6 )
Filtered Filtered
Figure 1. PRISMA flow diagram.
Filtered
Remove of duplication (n=1)
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2.9 Assessment of bias risk
The risk of bias assessment was conducted using a modified version of Tool to Assess Risk of Bias (Annex 1) in Cohort Studies by Cochrane Methods. (Table 2) References Was selection of exposed and non-exposed sample drawn from the same population? Can we be confident in the assessment of exposure ? Can we be confident that the outcome of interest was not present at start of study? Can we be confident in the assessment of the presence or absence of prognostic factors? Can we be confident in the assessment of the outcome? Were co-Intervatntions similar between groups ? Miethke RR. et Vogt S. 2005 [12] Definitely No High Risk Probably Yes Unidentified Definitely Yes Low Risk Probably No Unidentified Probably Yes Unidentified Probably Yes Unidentified Azaripour A. et al. 2015 [13] Definitely No High Risk Probably Yes Unidentified Definitely Yes Low Risk Probably Yes Unidentified Probably Yes Unidentified Definitely Yes Unidentified Levrini L. et al. 2015 [14] Probably Yes Unedintified Probably Yes Unidentified Definitely Yes Low Risk Probably Yes Unidentified Probably Yes Unidentified Definitely Yes Unidentified Abbate GM. et al. 2015 [15] Definitely Yes Low Risk Probably Yes Unidentified Definitely Yes Low Risk Probably Yes Unidentified Probably Yes Unidentified Definitely Yes Unidentified Levrini L. et al. 2013 [16] Definitely Yes Low Risk Probably Yes Unidentified Definitely Yes Low Risk Probably Yes Unidentified Probably Yes Unidentified Probably Yes Unidentified Chhibber A. et al 2017 [17] Definitely Yes Low Risk Definitely Yes Low Risk Definitely Yes Low Risk Probably Yes Unidentified Probably Yes Low Risk Definitely Yes Unidentified
Table 2. Assessment of risk of bias in included studies
Did the study match exposed and unexposed for all variables
that are associated with the outcome of interest or did the
statistical analysis adjust for these prognostic variables?
Definitely Yes Low Risk Definitely Yes Low Risk Definitely Yes Low Risk Definitely Yes Low Risk Definitely Yes Low Risk Definitely Yes Low Risk
14
2.10 Abbreviations:
Abbreviations and indices used in this systematic review to compare the periodontal status of the patients used in tables explained following:
Fixed Orthodontic Appliances (FOA), Gingival Index (GI) by Löe & Silness, Plaques Index (PI) by Löe & Silness,
Papillary Bleeding Index (PBI) by Saxer & Mühlemann [18-19]. (Annex 2) Approximal plaque index (API),
Sulcus bleeding index (SBI) by Lange et al [20], Bleeding on probing (BOP),
Sulcus probing depth (SPD).
Time periods at T0 (before treatment), T1 (1 month), T2 (2 months), T3 (3 months), T4 (6 months), T5 (9 months), T6 (12 months) and T7 (18 months) of the parameters stated above were assessed in this systematic review. It must be mentioned that not all authors followed the same indices and time measurements in their studies.
3. Results
3.1 Study selection
The primary search produced a total of 61 studies, of which 1 of those were duplicates. After a primary screening of the titles and abstracts according to the exclusion and inclusion criteria, 52 were excluded. By reviewing full-text articles, 2 articles were excluded due to limited access and not relevant content. In conclusion, 6 qualified studies involving 385 patients were enlisted in this systematic review. [12-17] Totally 194 patients in the fixed orthodontic appliances group, 171 patients in the Invisalign® group and the rest 20 patients were the control group in case control studies.
15
3.2 Systemization of data and characteristics of studies
Relevant data of interest on the previously stated variables and main characteristics of studies were collected and organised into table. (Table 3)
References Population Sample size Gender of Population Country of Clinical Trial
Age Groups Recruitme
nt time Types of Studies Evaluation methods and outcome methods Times measures Miethke RR. et Vogt S. 2005 [12] 30 FOA patients +30 Invisalign® patients Total sample Size:60 Male:17
Female:43 Germany 18-51 years old
Mean age:30.1 2002-2003
Prospective cohord study
GI, PBI, PI,
SPD T1, T2, T3 Azaripour A. et al. 2015 [13] 50 FOA patients +50 Invisalign® patients Total sample Size:100 Male:27 Female:63 Germany / Netherlands 11-62 years old Mean age FOA:16.3±6.3
Mean age for Invisalign®: 31.9±13.6 ___ Prospective cohord study (Cross-sectional study)
GI, SBI, API, MPI Specified time after treamtent Levrini L. et al. 2015 [14] 35 FOA patients +32 Invisalign® patients+10 CG Total sample Size:77 Male:25
Female:52 Italy 16-30 years old Mean age:24.3 ___ Prospective cohord study PI, SPD, BOP and microbial test T0, T1, T2 Abbate GM. et al. 2015 [15] 25 FOA patients +22 Invisalign® patients Total sample Size:47
___ Italy 10-18 years old 2012-2013 Prospective
cohord study SPD, PI, BOP
T0, T3, T4, T6, Levrini L. et al. 2013 [16] 10 FOA patients +10 Invisalign® patients+10 CG Total sample Size:30 Male:9
Female:21 Italy Mean:25.1±4.6 ___ Prospective cohord study PI, SPD, BOP and microbial test T0, T1, T2 Chhibber A. et al 2017 [17] 44 FOA patients +27 Invisalign® patients Total sample Size:71 Male:41 Female:30 Australia 14.66-16.49 years old Mean age:15.6 2011-2014 Radomized controlled clinical trial
PI, GI, PBI T0, T5, T7 Table 3: Characteristics of the qualified studies in this systematic review
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3.3 Evaluation of data
17
3.4 Comparison of indices in the chosen studies
GI index results showed no significant difference between patients with fixed orthodontic appliances and Invisalign® aligners. PBI index results also showed no significant difference between patients with fixed orthodontic appliances and Invisalign® aligners although the studies used different examination methods in the evaluation. The PI index showed significant difference between patients with fixed orthodontic appliances and Invisalign® aligners, however the studies used alternative methods for examination. SPD index results also showed no significant difference between patients with fixed orthodontic appliances and Invisalign® aligners even though the evaluation methods authors chose were not similar. Wide spectrum of treatment duration was used in each study which made it hard to evaluate it but it was possible to observe the certain chronological point where most indices had an increase in both appliances mainly in fixed orthodontic appliances patients during a period of 3-9 months.
3.5 Individualization of results from each study
Rainer-Reginald Miethke & Ailke Vogt [12] showed that the GI, and the PBI and the SPD were similar in the two treatment groups at the beginning of treatment. The only index that showed a significant difference at the first evaluation was the PI. Almost all indices improved from the first analysed assessment, though it was more visible for the Invisalign® group. The minimum alteration and/or improvement was seen in the SPD. In General, only the PI differed significantly among those patients treated with the Invisalign® system and those treated with fixed orthodontic appliances. A. Azaripour et al. [13] exhibited that there were distinguished changes in periodontal status in both patients groups during orthodontic treatment. Dental plaque measured by API index had increased in both patient groups but was higher in the fixed orthodontic appliances patients (37.7± 21.9) as compared to the Invisalign® patients (27.8± 24.6). According to author these differences were not significant. Invisalign® patients showed significantly better gingival conditions than fixed orthodontic appliances patients. There was hardly any increase in the GI and SBI values in Invisalign® patients during orthodontic treatment nevertheless there was a 2-fold increase in the GI and SBI values in fixed orthodontics appliances patients during treatment.
Luca Levrini et al. 2015 [14] displayed that a statistically significant difference was found between the Invisalign® group and the fixed orthodontic appliance group in all periodontal parameters (BOP,
18 PD, and PI), with the Invisalign® group recording lower values compared to the fixed orthodontic appliance group. The periodontal parameters showed the worst scores after 3 months compared to the beginning of treatment and after 1 month of treatment in the fixed orthodontic appliance group. The Invisalign® group showed a statistically significant increase in the PI values after 3 months of treatment. Furthermore, no statistically significant differences in the BOP and in the PD were observed. Another evaluation method that has been measured in this study demonstrated that the Invisalign® group showed a statistically significant difference in the total biofilm mass with a decrease score in the 3 months follow‑up examination. Additionally, the total biofilm mass showed a statistically significant difference between the Invisalign® group and the fixed orthodontic appliance group. Also the microbiological analyses detected the presence of A.actinomycetemcomitans in only one patient treated with fixed orthodontic appliances. At the last evaluation the mean bacterial concentration “C” was 104,536,026; 2739 and 8187 in the fixed orthodontic appliances, the Invisalign® and control group, respectively, being significantly increased in the first group as it is mentioned. Worth to be mentioned that besides the SPD value, no other values were statistically analysed in this study even though it was mentioned during evaluation of patients.
Gian Marco Abbate et al. [15] revealed from the beginning until the end of orthodontic treatment, the full mouth plaque scored tripled in value and full mouth bleeding scored doubled in value for adolescents with fixed orthodontic appliances, while both scores decreased slightly in the teenagers wearing Invisalign®. The plaque and bleeding indices recorded on the incisor and the molar also rose during the fixed orthodontic appliance treatment, however a reduction was observed during the Invisalign® treatment group. Probing depth was increased in all the treated patients, predominantly in the group with fixed orthodontic appliances. In addition they performed a microbial test and none of the patients tested positive for the anaerobic bacteria responsible for periodontal disease.
Luca Levrini et al. 2013 [16] The analyses of the correlation showed a statistical relation between the increase of microbial biofilm mass and the type of orthodontic treatment, increase of PI, BOP and a solid relation with the patient compliance to oral hygiene. A decrease of PD and BOP was detected in the Invisalign® group during treatment. The patients treated with fixed orthodontic appliances showed a higher value of both PD and BOP during treatment. The microbial biofilm mass obtained in the three different treatment groups were compared at the same PI value, it was possible to observe
19 that the removable treatment performed with the Invisalign® System induced a lower total biofilm mass accumulation compared to the treatment performed with fixed appliances. The microbiological investigation showed the presence of A. actinomycetemcomitans only in one patient treated with fixed orthodontic appliances.
According to the results of Aditya Chhibber et al [17] the Invisalign® group consistently presented the lowest mean values compared to the other 2 groups of fixed orthodontic appliances (self-ligated brackets and elastomeric ligated brackets). Especially, for PI, none of the odds ratios were significantly away from 1. Nevertheless, the odds ratios comparing the Invisalign® group with the fixed orthodontic appliances group for the GI and PBI were statistically significant at the 6 months’ evaluation. The Invisalign® group was 86% less likely than the fixed orthodontic appliances group to have some degree of gingival inflammation and 90% less likely to have papillary bleeding.
4. Discussion
It is shown in previous studies that fixed orthodontic appliances can encourage accumulation of dental plaque, eventually gingival swelling and gingival bleeding [21-23]. One of the most important factors in the given comparison is the role of duration of orthodontic treatment. According to Ristic et al [24] the GI index periodically increases at 4 weeks and 3 months after wearing fixed orthodontic appliances. Also in other studies and scholars it is been mentioned that wearing fixed orthodontics appliances during 5 to 6 months is the peak of development of gingivitis.
According to the results of the selected studies most of the author agreed that from all indices that are evaluated (GI,PBI,PI,SPD,SBI,API and BOP) only PI index showed significant improvement in patients that were treated with Invisalign® aligners in comparison to the patients that were treated with Fixed Orthodontic appliances. The possible explanations could be factors that Invisalign® patients can clean the appliance outside the oral cavity and remove the appliance during brushing and flossing which is a critical point to maintaining optimal oral hygiene for the patient.
Also another possible reason is that Invisalign® aligners cover the majority of crown thus partially preventing dental plaque from accumulating on the surface and also the transition of supragingival dental plaque to subgingival tissues to cause destruction of the periodontal tissues.
In accordance with Talic NF [25] that oral hygiene procedure has a major influence on the periodontal status of orthodontic patients despite the type of appliances that have been used. In addition, Invisalign® aligners tend to be suitable for patients with certain limitations, either dexterity or mental retardation, due to the difficulty of those patients to keep oral hygiene to acceptable range.
20 Van Gastel et al.[26] came to the conclusion via a de novo plaque growth experiment over a 7 day period, using different sorts of orthodontic brackets with non-bonded control teeth, that fixed orthodontic appliances can have a substantial impact on bacterial load. This conclusion is consistent with Luca Leverini et al.a [14] and Luca Levrini et al.b [16]
The following limitations of this systematic review and the studies that were included in should be mentioned. Most of the screened studies used time duration for their result from months 3 to 6 and most of the indices are increasing until their peak on the 6th month and then normalize periodically. Most of the chosen studies are from European countries, mainly Italy and only one from Australia. That lead to lacking of comparative researches from other countries.
The role of malocclusion in periodontal health is also important according to Anne-Marie Bollen [27]. The type of malocclusion is not specified in the current studies and it has not been taken into consideration.
The indices measured in this review were not the same in factors like position of teeth, number of teeth, measuring side that been used from each tooth. Also some articles used full mouth evaluation, some specific teeth evaluation and other did not explain their evaluation method.
It is known that periodontal status varies from adolescent patients to adult patients mainly due to hormonal changes. Different patients of a wide spectrum of ages have been used in this systematic review, but it was not possible to evaluate the differences in results among them due to the lack of information. Adults are usually more cooperative than adolescences in regard oral hygiene. In addition, adolescences experience more gingival overgrowth due to hormonal changes.
The studies included in this systematic review were mainly prospective cohort studies and only one randomized control study. That, inevitably will lead to insufficient amount of information for comparison and bias will appear. Never the less, the quantity and quality of articles were insufficient thus more studies, specifically more randomized control studies must be done to confirm our hypothesis.
5. Conclusions
Patients treated with Invisalign have better periodontal health according to the periodontal indices measurement in comparison with patients treated with the traditional fixed orthodontic appliances. Oral hygiene was better in patients with Invisalign® aligners compared to patients with fixed orthodontic appliances due to Invisalign®aligners removable nature. Treatment duration should also be considered because until 6 to 9 months when it was being examined, because it was the peak of
21 periodontal indices due to the application of the appliance especially in the case of treatment with fixed orthodontic appliances.
6. Practical Recommendations
According to this systematic review, from the perspective of achieving and maintaining optimal periodontal health, Invisalign® aligners are a greater option. Although, Invisalign® aligners are a novel, sensitive and not indicated for all cases technique but it should be presented whenever it is indicated. It is also very important for doctors to advice the patients on how to properly brush their teeth during orthodontic treatment and explain the importance of oral hygiene, regardless of the type of treatment that is selected.
7. References
1. Alfuriji S, Alhazmi N, Alhamlan N, Al-Ehaideb A, Alruwaithi M, Alkatheeri N, Geevarghese A. The Effect of Orthodontic Therapy on Periodontal Health: A Review of the Literature. Int. J.
Dent. 2014;585048.
2. Dannan A., An update on periodontic-orthodontic interrelationships, J. Indian Soc. Periodontol., 2010; 14(1), 66–71.
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24
Annex 1
Tool to Assess Risk of Bias in Cohort Studies
1. Was the selection of exposed and non‑exposed cohorts drawn from the same population? Examples of low bias risk: Exposed and unexposed drawn from the same administrative data base of patients presenting at the same care points over the same time frame. Examples of high bias risk: exposed and unexposed presenting to different care points or over a different time frame.
2. Can we be confident in the assessment of exposure?
Examples of low bias risk: Secure record [e.g. surgical records, pharmacy records]; Repeated interview or other ascertainment asking about current use/exposure. Examples of higher bias risk: Structured interview at a single point in time; Written self-report; Individuals who are asked to retrospectively confirm their exposure status may be subject to recall bias – less likely to recall an exposure if they have not developed an adverse outcome, and more likely to recall an exposure (whether an exposure occurred or not) if they have developed an adverse outcome. Examples of high bias risk: uncertain of how the exposure information was obtained.
3. Can we be confident that the outcome of interest was not present at start of study?
4. Did the study match exposed and unexposed for all variables that are associated with the outcome of interest or did the statistical analysis adjust for these prognostic variables?
Examples of low bias risk: comprehensive matching or adjustment for all plausible prognostic variables. Examples of higher bias risk: matching or adjustment of most plausible prognostic variables. Examples of high bias risk: matching or adjustment of a minority of plausible prognostic variables, or no matching or adjustment at all. Statements with no differences between groups or with differences that were not statistically significant are not sufficient for establishing comparability. 5. Can we be confident in the assessment of the presence or absence of prognostic factors?
Examples of low bias risk: Interview of all participants; self‑completed survey from all participants; review of charts with reproducibility demonstrated; from data base with documentation of accuracy of abstraction of prognostic data. Examples of higher bias risk: Chart review without demonstration of reproducibility; data base with uncertain quality of abstraction of prognostic information. Examples of high bias risk: Prognostic information from data base with no available documentation of quality of abstraction of prognostic variables.
6. Can we be confident in the assessment of outcome?
25 fractured hip), reference to the medical record is sufficient to satisfy the requirement for confirmation of the fracture. Examples of higher bias risk: Independent assessment unblinded; self‑report; For some outcomes (e.g. vertebral fracture, where reference to x‑rays would be required) reference to the medical record would not be of adequate outcome.
7. Was the follow up of cohorts adequate?
Examples of low bias risk: No missing outcome data; Reasons for missing outcome data unlikely to be related to true outcome (for survival data, censoring is unlikely to introduce bias); Missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups. For dichotomous outcome data, the proportion of missing outcomes compared with observed event risk is not enough to have a important impact on the intervention effect estimate. For continuous outcome data, plausible effect size (difference in means or standardized difference in means) among missing outcomes is not large enough to have an important impact on the observed effect size. Missing data have been imputed using appropriate methods. Examples of high bias risk: Reason for missing outcome data likely to be related to true outcome, with either an imbalance in numbers or reasons for missing data across intervention groups. For dichotomous outcome data, the proportion of missing outcomes compared with observed event risk is enough to induce important bias in intervention effect estimate. For continuous outcome data, plausible effect size (difference in means or standardized difference in means) among missing outcomes is large enough to induce clinically relevant bias in the observed effect size.
8. Were co‑Interventions similar between groups?
Examples of low bias risk: Most or all relevant co‑interventions that might influence the outcome of interest are documented to be similar in the exposed and unexposed. Examples of high bias risk: Few or no relevant co‑interventions that might influence the outcome of interest are documented to be similar in the exposed and unexposed
26 Annex 2
Scoring criteria for the periodontal indices (PI, GI, and BI)
Scoring Plaque Index (PI)
0 No plaque/debris on inspection and probing 1 Thin film of plaque only visible after probing
2 Ribbon-like layer of plaque covering the sulcus & gingival crown areas but not filling interdental spaces
3 Thick layer of plaque already visible at inspection and filling interdental space
Scoring Gingival Index (GI)
0 Physiologic gingiva
1 Mild Inflammation (slight colour change and little change in texture)
2 Moderate inflammation (moderate glazing, redness, edema and hypertrophy, bleeding on probing
3 Sever inflammation (marked redness and hypertrophy, ulceration, tendency to bleed spontaneously
Scoring Papillary Bleeding Index (PBI)
0 No bleeding
1 Singular bleeding point
2 Several bleeding points or a thing bleeding line along the marginal gingiva 3 Bleeding the entire interdental gingival triangle immediately after probing
4 Profuse bleeding during probing, bleeding extending over the marginal gingiva eventually with development of blood drops
