The Effect of Two Different Types of Forces on Possible Root Resorption in Relation to Dentin Phosphoprotein Levels

The Effect of Two Different Types of Forces on Possible Root Resorption in Relation to Dentin Phosphoprotein Levels

The Effect of Two Different Types of Forces on Possible Root Resorption in Relation to Dentin Phosphoprotein Levels: A Randomized Controlled Clinical Trial

External root resorption is a common unfavourable sequel of orthodontic treatment. Although diagnosis of root resorption is usually done by radiographs; they are technique sensitive. Dentine phosphoprotein, a non-collagenous protein, is suggested to be released into the gingival crevicular fluid during active root resorption, serving as a good diagnostic tool. Also, the manner of force application is a modifiable factor suggested to affect root resorption.

Early detection of teeth at risk of severe resorption is crucial.At present, using radiographs is common but detecting only resorption after 60-70% of the mineralized tissue is already lost. Moreover, they only provide two-dimensional information, identifying apical change primarily. Also, radiographs cannot indicate if the process of root resorption is still active for monitoring its progress and additional radiation exposure to the patient will be needed. Therefore, a safer, more reliable alternative method to clinically diagnose early stages of root resorption is needed and may include detecting biomarkers in gingival crevicular fluid. Furthermore, the relationship between the manner of orthodontic force application and orthodontically induced root resorption is under study. It has been suggested that pausing orthodontic forces during treatment may reduce the amount of root resorption, likely due to cementum repair during the inactive period. This is important specifically in individuals who are biologically and genetically prone to root resorption. The aim of the study is to compare the extent of root resorption between controlled continuous and intermittent orthodontic forces using levels of dentin phosphoprotein in gingival crevicular fluid.

Root resorption, Gingival crevicular fluid, Dentin Phosphoprotein, Continuous force, Intermittent force

A buccally directed continuous tipping force of 150 g is applied to the maxillary first premolar on one side

A buccally directed tipping force of 150 g removed every 21 days for a 7-day rest period applied to the maxillary first premolar on one side

A buccally directed continuous tipping force of 150 g is applied to the maxillary first premolar by a cantilever spring made of 0.017" x 0.025" beta-titanium-molybdenum alloy inserted in the tube of the upper first molar, bypassing the second premolar and attaching to the upper first premolar. The buccal tipping force will be checked and reactivated to the original level on the 28th day of the 8 week study period.

A buccally directed tipping force of 150 g is applied to the maxillary first premolar by a cantilever spring made of 0.017" x 0.025" beta-titanium-molybdenum alloy inserted in the tube of the upper first molar and attaching to the upper first premolar. The buccal tipping force will be removed every 21 days for a 7-day rest period, where a passive wire of the same gauge and material of the cantilever spring (0.017" x 0.025" beta-titanium-molybdenum alloy) will be placed instead to maintain the position of the upper first premolar during the rest period.

Evaluate and compare the possible effect of continuous and intermittent orthodontic forces on root resorption using dentin phosphoprotein levels.

Inclusion Criteria: Malocclusion that requires extraction of first maxillary premolars on both sides. No previous reported or observed dental treatment to the teeth to be extracted. No previous reported or observed trauma to the teeth to be extracted. No previous reported or observed orthodontic treatment involving the teeth to be extracted. Free of any systemic disease affecting the dentition. Exclusion Criteria: Past or present signs or symptoms of periodontal disease. Past or present signs or symptoms of bruxism.

Ghaleb S, Tamish N, ElKenany W, Guindi M. The effect of two different types of forces on possible root resorption in relation to dentin phosphoprotein levels: a single-blind, split-mouth, randomized controlled trial. Prog Orthod. 2021 Dec 20;22(1):44. doi: 10.1186/s40510-021-00388-y.