Table 4.
Description of the results of the studies included in the systematic review demonstrating tissue and biochemical changes during orthodontic retention.
| Author, year | Type of study | Outcome measure | Site of expression &/or method of assessment | Results |
|---|---|---|---|---|
| Reitan (30) | Review | Principle fibers of the periodontium especially supraalveolar fibers | In different areas of the root based on the type of tooth movement | After derotations, principle fibers returned to original positions in a few days; supraalveolar fibers took approximately 232 days |
| Murell et al. (31) | Animal | Number of blood vessels | Periodontal ligament | 12–50 micron diameter: Numbers around middle third of root increased and peaked in 3 days and declined over the next 2 weeks 51–200 micron diameter: Numbers around the cervical third of root decreased in the first two days and increased the next two days after which returned to baseline levels |
| King et al. (21) | Animal | Histological: osteoclast numbers per millimeter of bone surface, osteoclast surface percentage, osteoblast surface percentage, mineralizing surface percentage, mineral apposition rate, bone formation rate, and percentage of resorbed root surface | First molar sections for histomorphometry and sera and aparadental alveolar bone for the biochemical assay | Histological: Mesial end of molar—osteoclast number and surface % elevated 3.5 to 4 times on day 1 and returned to baseline by day 5. Distal end of molar—No time- related treatment effects on osteoclast number and surface % |
| Biochemical: Bone phosphatases (acid phosphatase, TRAP, alkaline phosphatase), bone remodeling parameters (osteoblast and osteoclast percentage) | Biochemical: Significant elevations in acid phosphatase and TRAP in the treated tissues at days 5, 7, and 10. No time- or treatment-related differences in serum alkaline phosphatase activities | |||
| Franzen et al. (20) | Animal | Bone architecture: Bone mineral density, percent bone volume, bone surface density, total porosity. | Micro ct of alveolar bone RTPCR to evaluate bone formation markers runx2, COL1A1, ALP, OCN and bone resorption markers H + -ATPase, TRAP and RANKL | Relapse upto 93% by 21 days |
| 1st day—73% relapse (rate of 140 microns/day | ||||
| 2nd to 21st day—93% relapse (Rate almost negligible) | ||||
| Microct evaluation: Tissue mineral density decreased During OTM and returned to baseline levels 3 days after removal Biomarkers—ALP, OCN, COL1A1, Runx2—No significant correlation with relapse | ||||
| RANKL—Decrease after appliance removal till baseline by 21 days | ||||
| TRAP—Insignificantly increased till 7 days after appliance removal then returned to baseline levels by 21 days | ||||
| Perinetti et al. (33) | Human | Periodontal health: Supragingival plaque, bleeding on probing, pocket depth | Gingival Crevicular fluid | Periodontal Health: Plaque & bleding on probing: No significant differences between test teeth (TT) (maxillary first molar) and mandibular first molar (CT) (control teeth) at T1 (3months) and T2 (6 months) post expansion |
| Alkaline phosphatase | Pocket depth: Significant differences between TT & CT at T1 and T2 | |||
| Alkaline phosphatase: Significant increase at the TT site Significant increase at T1 & T2 at the TT site | ||||
| Burke (32) | Human | Total secretory proteins and cyclic adenosine monophosphate (c- AMP)—dependant protein kinase subunit (RII) | Saliva and Gingival Crevicular fluid; Electrophoresis and Western blotting | Electrophoresis: Total protein concentration—No significant increase in GCF and saliva (Increased in some and decreased in other patients) |
| Western blotting: c-AMP dependant protein kinase subunit (RII)—No significant increase in GCF and saliva (Increased in some and decreased in other patients) 50-to-55 kd bands, characteristic of RII, disappeared, while a fragment in the 20 to 30-kd range increased considerably after separator placement | ||||
| Awag- Kechik et al, (22) | Human | Protein profile | Saliva; Liquid Chromatography‒Mass Spectrometry (LC‒ MS) | Little's Irregularity index: Significant difference in irregularity in mandibular arch 6 months into retention phase Protein profile: Active phase—146 proteins Retentive phase—135 proteins 15 proteins expressed in both active and retentive phase 1 protein (tyrosine protein kinase) expressed only in retentive phase |