1. What data in particular will be shared?
   Response - Individual participant data that underlie the results reported in this article, after de-identification (text, tables, figures, and appendices).
   


2. What additional supporting information will be shared?
   Response -  Study Protocol
   Response -  Statistical Analysis Plan
   Response - Informed Consent Form
   Response - Clinical Study Report
   Response -  Analytic Code
   
   
3. Who will be able to view these files?
   Response - Anyone
   


4. For what types of analyses will this data be available?
   Response - Any purpose.
   


5. By what mechanism will data be made available?
   Response - Proposals should be directed to [dr.rishika89@gmail.com].
   


6. For how long will this data be available start date provided 10-11-2023 and end date provided 10-01-2025?
   Response - Beginning 3 months and ending 5 years following article publication.
   


7. Any URL or additional information regarding plan/policy for sharing IPD? 
   Additional Information - NIL

NOVELTY-Even though there are numerous hypotheses stating MMP-9 and its presence as a biomarker in gingival crevicular fluid during bone/root resorption, no such studies have been conducted to prove the hypothesis. There is a lacuna seen in this aspect of research.

OBJECTIVES-

PRIMARY OBJECTIVE- To observe any correlation of MMP-9 levels in gingival crevicular fluid in two groups of patients treated with and without midline mini implants for intrusion of anterior teeth to the severity of orthodontically-induced external root resorption

STUDY DESIGN – Prospective cohort study

 STUDY SETTING –      Department of Orthodontics and Dentofacial Orthopedics, MES Dental College, Perinthalmanna.Department of Microbiology, MES Medical College, Perinthalmanna.

 STUDY PERIOD AND TIMELINE - 15/09/2023 – 01/01/2024

 STUDY POPULATION-The sample for this study will include two groups of patients assigned for fixed orthodontic treatment in the Department of Orthodontics and Dentofacial Orthopedics, MES Dental College, Perinthalmanna.

1.Group 1 – Patients with Angle’s Class I bimaxillary dentoalveolar protrusion malocclusion who will be treated with fixed orthodontic treatment for retraction of anterior teeth following therapeutic extraction of first premolar teeth.

2. Group 2 – Patients with Angle’s Class I bimaxillary dentoalveolar protrusion malocclusion with increased visibility of maxillary anteriors >4mm who require simultaneous intrusion and retraction of the anterior segment with a midline Mini implant (Absoanchor, Dentos, 1312 NH 7mm) following therapeutic extraction of first premolar teeth.

DATA COLLECTION METHOD

GCF COLLECTION

The maxillary incisor teeth (11,12,21,22) where the samples will be collected are first isolated with the cotton rolls and dried with air. The gingival crevicular fluid will be collected by placing PerioPaper strips (Oraflow Inc.Hewlett, New York, USA ) into the gingival sulcus of maxillary central and lateral incisors. This will be taken from the mesio-buccal and disto-buccal aspect of the gingival sulcus, until a mild resistance is felt and left in place for 30s . Strips contaminated with blood will be excluded. . Samples will always be taken from same sites. All strips with gingival crevicular fluid will be stored in sterile Eppendorf vials containing phosphate-buffered saline. This will be centrifuged for 10 min at 4⁰ and will be stored at -20⁰, in the Department of Microbiology, MES Medical College, Perinthalmanna until all samples are collected. Each aliquot will be thawed to room temperature at the time of test. The samples will be assayed by ELISA Kit with 96T (Shanghai Korain Biotech Co.Ltd Bioassay). All assay procedures will be carried out according to the manufacturer’s instructions. Quantitative analysis will be done at the end of the assay at the Department of Microbiology, MES Medical College, Perinthalmanna.

RVG

The images will be analyzed and the Modified Malmgren Grading Criteria  will be used to measure the extent of external apical root resorption

EXPECTED OUTCOME-Primary outcome to be measured will be difference in the level of MMP-9 in the two groups of patients at different clinical time-points. Secondary outcome to be observed will be assessment of the extent of root resorption at three months following the start of retraction.

BENEFITS FROM OUTCOME- MMP-9 is expressed as an extracellular matrix protein by osteoclast. Its presence often indicates an active bone/root resorption which indicated tooth movement. Bone resorption appears in radiographs at a later stage of treatment. The early detection of MMP-9 in the gingival crevicular fluid occurs at an earlier stage and can be taken as a predictive marker for active bone/tooth resorption.