Evaluating Laser and Piezocision vs. Piezocision Alone on Root Resorption and Gingival Health During Tooth Retraction

Class II, Division 1 malocclusion is a common condition often treated by extracting upper premolars and retraction of the front teeth (en-masse retraction). This phase can take 9-12 months, increasing the risk of complications like poor oral hygiene, gum inflammation, and external apical root resorption (EARR). To address this, methods to accelerate tooth movement have been developed, including surgical (piezocision) and non-surgical (LLLT) techniques. While these methods aim to reduce treatment time, their combined effects on safety outcomes, such as EARR and periodontal health, are unclear. This three-arm randomized controlled trial evaluates the effects of en-masse retraction assisted by piezocision combined with LLLT (FC+LLLT), compared to piezocision alone (FC) and conventional treatment (CONT). Sixty-six patients were randomly assigned to the three groups. The piezocision procedure involved 18 minimal incisions and cortical bone perforations using a piezosurgery tip. The FC+LLLT group received adjunctive Ga-Al-As diode laser (808 nm, 1.1 W, 4 J/point) at multiple sessions. En-masse retraction was performed with 250g force using Ni-Ti coil springs from mini-screws. EARR was measured on standardized panoramic radiographs at T0 (pre-treatment), T1 (pre-retraction), and T2 (post-retraction) using a crown-length correction method. Periodontal health (Gingival Index, Papillary Bleeding Index, Dental Plaque Index, and Gingival Recession) was assessed at the same time points. The study aims to determine if these acceleration techniques increase the risk of these iatrogenic complications.

Inclusion criteria

• Healthy patients aged 17-28 years.
• Diagnosed with a Class II division 1 malocclusion, indicated for extraction of the upper first premolars, with an overjet of 4-10 mm and a normal or increased facial height assessed clinically and cephalometrically using three angles (MM= 23ᵒ-33ᵒ, Jarabak Ratio ≤ 64%, and Y-axis angle= 66ᵒ-75ᵒ)
• A skeletal Class II relationship, confirmed by a cephalometric ANB angle between 4° and 7°
• An overbite of 0%-33%
• Good oral hygiene, defined by a probing depth of ≤3 mm and no radiographic evidence of alveolar bone loss
• Absence or a mild level of crowding
• A full complement of teeth, excluding third molars.

Exclusion criteria

• A history of previous orthodontic treatment
• Any systemic disease or medication known to interfere with orthodontic tooth movement.
• Congenitally missing or extracted teeth in the maxilla (except third molars)
• Poor oral hygiene,
• Active periodontal disease (probing depth ≥4 mm, radiographic bone loss, gingival index >1, plaque index >1)
• Moderate to severe maxillary crowding (Little's Irregularity Index ≥4).