Impact of Increased Body Mass Index on Adolescent Fixed Orthodontic Treatment. A Prospective Longitudinal Study

Bleeding on probing (BOP) will be assessed dichotomously (yes/no) at six sites per tooth (mesio-buccal, mid-buccal, disto-buccal, mesio-lingual/palatal, mid-lingual/palatal, and disto-lingual/palatal) using a standardized periodontal probe by trained examiners. The full-mouth bleeding score (FMBS) will be calculated as the percentage of sites that bleed out of the total number of sites examined. Higher percentages indicate greater gingival inflammation.

Standardized intraoral and facial photographs will be taken using calibrated camera settings and stored in Dolphin Imaging Software. Each visible tooth surface will be examined for color, texture, and cavitation changes and scored using the International Caries Detection and Assessment System (ICDAS). Code 0 = sound surface; code 2 = visible white spot lesion; codes 3-4 = localized enamel breakdown or dentin shadowing; codes 5-6 = cavitated lesions extending into dentin. Because photos are obtained without air drying, code 1 will be excluded. The average WSL score per participant will be calculated by dividing the total ICDAS score by the number of surfaces assessed. Mean change = score at T2 minus score at T1. Higher scores indicate greater enamel decalcification.

Unstimulated whole saliva will be collected at baseline and follow-up. C. albicans will be cultured on CHROMagar™ Candida and confirmed via germ tube test from three colonies per sample. S. mutans will be cultured on Mitis Salivarius Bacitracin medium and identified by colony morphology. DNA-based microbial identification and oral microbiome sequencing with bioinformatics analysis will also be performed. Microbial counts will be reported per participant as colony-forming units per milliliter (CFU/mL) or relative abundance. Higher values indicate greater microbial load.

Height (cm) will be measured using a stadiometer, and weight (kg) with a calibrated digital scale. BMI will be calculated as weight (kg)/height² (m²). Measurements will be taken twice and averaged. Higher BMI indicates greater body mass relative to height.

Plaque presence will be recorded on four surfaces per tooth (mesial, distal, buccal, lingual/palatal). The FMPS will be calculated as the percentage of surfaces with plaque present out of total surfaces examined. Higher percentages indicate poorer oral hygiene.

Probing depth (PD) will be measured at six sites per tooth using a periodontal probe. The percentage of sites with PD greater than 3 mm will be calculated for each participant. Higher percentages indicate more severe periodontal disease.

Oral dryness will be assessed using the Challacombe Scale, which rates 10 indicators of xerostomia (e.g., lack of saliva pooling, frothy saliva, depapillation, fissured tongue). Scores range from 1 to 10, with 1-3 indicating mild dryness, 4-6 moderate, and 7-10 severe. Higher scores indicate greater dryness.

Dental casts made from alginate impressions will be analyzed using a digital caliper (accuracy 0.01 mm). The sum of the linear displacements between the anatomic contact points of the mandibular incisors (five measurements) yields Little's Irregularity Index. Higher values indicate greater misalignment.

Salivary and gingival crevicular fluid samples will be centrifuged and analyzed using multiplexed magnetic bead assays (Milliplex MAP). Concentrations will be calculated from standard curves. Higher levels indicate greater inflammatory activity.

Participants will complete a standardized questionnaire assessing dietary habits related to oral health and obesity. Responses will be scored to produce a composite dietary habits score; higher scores indicate less healthy dietary patterns.

The Oral Health Impact Profile-14 (OHIP-14) questionnaire will assess functional limitation, pain, and psychological and social impacts of oral health. Scores from 14 items are summed (range 0-56); higher scores indicate poorer oral health-related quality of life.