Comparison of Oral Hygiene & Root Resorption During Orthodontic Treatment

Importance of the research Orthodontic treatment is no longer limited mainly to children and
adolescents. With increasing number of patients from older age groups seeking orthodontic
treatment; there has been an increasing demand for esthetic alternatives to conventional
fixed stainless steel appliances. Some issues associated with conventional fixed appliances
for treatment are: 1) unaesthetic appearance of brackets especially for adult patients, many
of whom are unwilling to wear braces, 2) conventional systems compromise the ability of the
patient to maintain good oral hygiene; 3) increase the risk of periodontal breakdown due to
constant accumulation of plaque around the brackets, wires and ill-fitting bands; 4) require
many follow-up visits for appliance reactivation and adjustment if the teeth do not move as
desired; 5) iatrogenic root resorption, a major medico-legal concern also poses significant
problems for the clinician. Increased use of self-ligating brackets and clear aligners from
Invisalign (Align Technology, Inc., Santa Clara, CA) are some of the recent developments in
orthodontics that have tried to address these concerns. However clinical evidence
highlighting their efficacy has not been quiet forthcoming. Present knowledge is primarily
based upon case reports, case series, surveys, anecdotal reports and retrospective studies.
In such a scenario it is imperative to find an optimized evidence-based treatment strategy
that leads to predictable outcome with complete patient satisfaction during and after
treatment while minimizing the risk for root resorption and periodontal breakdown.

RESEARCH DESIGN & METHODS:

Screening procedure:The patients were selected from the Division of Orthodontics, Department
of Craniofacial Sciences, University of Connecticut, Health Center by two orthodontists: the
faculty member supervising the 'clinical component' of the research and the faculty member
supervising the microbiological and radiological part of the research.

Only after gaining approval from both the faculty members was a patient be selected for the
study. The patients and their parents were provided with a written explanation on the
background of the study, its objectives, and their involvement. In addition to the consent
form for routine orthodontic care currently used in our clinic; the patient or
parent/guardian of every patient was given a second consent form specifically related to
this study. The following were the inclusion criteria, which are based on previous studies
and our clinical research experience:

1. All the patients should be physically healthy with no relevant allergies or medical
problems.

2. All patients ≥ 12 years of age.

3. There should be less than 8mm of anterior crowding or spacing and adequate buccal
interdigitation. Patients with posterior edentulous spaces will only be included if
treatment does not entail space closure.

4. Patients should have all permanent teeth present, except third molars.

5. Demonstrable ability to maintain adequate oral hygiene.

6. Show optimum dental health without immediate need for restorations.

Following will be the exclusion criteria:

1. Skeletal anterior-posterior discrepancies between the maxilla and mandible (ANB ≥ 5°).

2. Centric relation (CR)- Centric occlusion (CO) discrepancies of greater than 3 mm.

3. Anterior or posterior open bites.

4. Patients who are pregnant, diabetic or using mouth rinses or interacting medications,
including antibiotic therapy.

5. Presence of active periodontal disease.

6. Presence of impacted teeth.

7. Smoking

The patients who fulfilled the above criteria were randomly assigned to one of the treatment
groups. The statistician on this project used a computer-generated random numbers ('Rand'
function, Microsoft, Excel 2011) for allocation of the sequence. This ensured even
distributions of the patients in all the groups. Computer generated random numbers also
randomized the right and the left sides of the maxilla for selecting the experimental side.

Sample size From previous studies, it was inferred that a mean colony forming unit (CFU)
unit difference of approximately one log (standard deviation (SD) = approximately 1) would
result in a clinically significant increase in S.mutans counts. Therefore the sample size of
15 patients per group, at α = 0.05, yielded a statistical power of approximately 0.80 for
this study. To account for a 10-20% patient drop out and data loss due to other unavoidable
circumstances, we will enroll 60 patients for this study.

Specific aim #1: Measuring the gingival health

Periodontal measurements were recorded specifically for the upper maxillary lateral incisor
and second premolar.One individual took all study related periodontal measurements at three
different time intervals:

T0: before treatment, T1: after 9 months of treatment &T2: after 18 months of treatment.

During all the measurements, the examiner was blinded from the previous scores. Prior to the
start of the research, all patients received standardized oral hygiene instruction to ensure
a healthy periodontium.

Goal 1: Measuring the gingival Status The gingival index (GI) developed by Loe and Silness
was used.Grades of the severity of gingivitis was scored by clinical inspection based on the
size, color, and texture of the gingival margin adjacent to the bracket and bleeding on
probing.

Goal 2: Measuring the plaque index (PI) The PI was assessed according to the plaque
accumulation in the gingival area in four grades by guiding a probe gingivally over the
buccal surface of the selected teeth.

Goal 3: Measuring the papillary bleeding index (PBI) Bleeding on probing (BOP) tendency was
measured at the proximal buccal side of the selected teeth, 20 seconds after probing the
depth of the pocket/gingival sulcus. The PBI will be assessed in five grades by guiding a
probe carefully along the marginal sulcus while observing bleeding intensity.

Specific aim #2: Estimating the total bacterial and Streptococcus mutans count in the plaque
sample.

Goal 1: Collection of plaque specimen After isolating the teeth from saliva with cotton
rolls and gently drying them to prevent contamination, the supragingival plaque was
carefully removed without traumatizing the gingiva, as this would increase the production of
gingival crevicular fluid. 52 The plaque-sampling investigator used a standardized protocol
to collect specimens at all the three time intervals. Plaque specimens were collected from
the labial surfaces immediately surrounding the orthodontic brackets with a sterilized
dental scaler with the same tip dimensions (#8/9 Orban DE hoe scaler, Hu-Friedy, Chicago,
Ill). Because the area of increased decalcification was generally immediately adjacent to
the brackets, four passes, 1 each along the tooth at the bracket interface at the gingival,
mesial, distal, and occlusal aspects, were made to avoid overloading the instrument tip. For
the invisalign group a single circular stroke around the center of the clinical crown was
made. All specimens from each tooth were placed into individual tubes with anonymous coding
and sealed for transport to the laboratory. The coding of the specimens ensured blinding of
laboratory personnel and help minimize experimental bias.

Goal 2: Microbial sampling Each specimen was diluted in 2 ml of phosphate buffered saline
(PBS) dilute yeast extract and the samples will be sonicated for 10 sec before doing serial
dilutions. Then 1 ml was submitted to tenfold serial dilution in 9 ml of yeast extract.
After each serial dilution the test tubes were vortexed for 10 sec. Ten microlitre (10 μl)
of supernatant was then plated onto Tripticase soy agar supplemented with 5% sheep bovine
blood (BBL) for total bacterial evaluation and mitis salivarius-bacitracin agar specific for
S. mutans. The samples were processed within 2 hours and the plates incubated for 24 hours
at 37°C. The number of total CFU (Colony forming unit), specific to S. mutans was identified
and counted by the blinded investigator which represented the total recoverable facultative
flora.

Specific aim # 3: Estimating the external apical root resorption (EARR) of the maxillary
incisors For each patient periapical films of the maxillary incisors and the premolars &
orthopantographs (OPG) were taken at the two different time points (T0 & T2). All the
periapical films were developed under similar conditions (Dentax 810 Basic) scanned with a
ruler to a computer, calibrated and measured in a 1:1 ratio with Adobe Photoshop software
(Adobe, San Jose, Calif) for measurement purposes. If required for better interpretation the
image of the tooth was enlarged and/or printed.

Measuring root resorption Root and crown length were measured with a sliding caliper to the
nearest 0.1 mm The enlargement factor of the second film was adjusted to the first film in
each case by reference to the registered crown length, which was assumed to be unchanged by
orthodontic treatment.

We used the 'rule-of-three formula' to calculate root length changes due to orthodontic
treatment. It is assumed that during orthodontic treatment the crown length does not change
(unless it is fractured). Therefore, the ratio between the initial crown length (C1) and the
final crown length (C2) determines the enlargement factor. If no changes occurred in the
root length during treatment, the ratio between the initial root length (R1) and the final
root length (R2) should be equal to the C1/C2 ratio. If during treatment the root was
shortened, the amount of OIIRR is R1-R2 (C1/ C2).

All research data was identified by unique identifier (Patient1, Patient 2 …) that contained
no PHI. Specifically, all data collected from the experiments was not associated with
patient's name, medical ID number, or any other identifier, which could readily identify the
patient. All patient data that was gathered was transferred immediately to a secure database
where the data was identified only by unique identifiers that were created for each patient.

Inclusion Criteria:

1. physically healthy with no relevant allergies or medical problems;

2. above 12 years of age at commencement of treatment;

3. in permanent dentition;

4. less than 5 mm of anterior crowding or spacing with adequate overjet and overbite;

5. ability to maintain adequate oral hygiene

6. in optimum dental health without immediate need for any allied dental procedure.

Exclusion Criteria:

1. skeletal anterior-posterior discrepancies between the maxilla and mandible (ANB ≥
5°);

2. centric relation - centric occlusion discrepancies of greater than 3 mm;

3. presence of active periodontal disease.