An observational study in Crowding, Tooth and Gingival Diseases, sponsored by Fondazione Policlinico Universitario Agostino Gemelli IRCCS. Recruiting at 1 site in Italy. Open to participants aged 5 Years to 16 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-05-26.
Sponsored by Fondazione Policlinico Universitario Agostino Gemelli IRCCS · Observational
The periodontal phenotype influences treatment outcomes across dental specialties, as tissues of different thickness respond differently to chemical, bacterial, and mechanical insults. In pediatric patients, understanding the gingival phenotype is particularly relevant: a thin phenotype may predispose to dehiscence, fenestration, and gingival recession-especially at the mandibular incisors-when tooth movement exceeds the biological limits of the bony housing.
During the mixed dentition phase, significant changes in soft and hard tissues affect tooth position and periodontal stability, making early phenotype assessment essential. Interceptive orthodontics can reduce the long-term risk of mucogingival defects; early identification of a thin biotype allows for preventive strategies, including soft tissue grafting before critical orthodontic movements.
No studies have examined the association between dental crowding severity and periodontal phenotype in children. Adult data remain inconsistent: Kaya et al. found no correlation between phenotype and skeletal malocclusion, while Kong et al. reported a site-specific association between thin biotype and skeletal Class I/III at the mandibular central incisor. No predictive model exists for periodontal risk related to severe crowding in childhood.
This study aims to assess the periodontal phenotype in pediatric patients across different stages of dental transition and to investigate a possible association between a thin periodontal biotype and severe dental crowding.
Background and Rationale
The periodontal phenotype-defined by the bucco-lingual thickness of the gingiva, the width of keratinized tissue, and the underlying bone morphology-plays a central role in the response of periodontal tissues to orthodontic forces, bacterial insults, and restorative or surgical procedures. Thin-scalloped phenotypes are associated with a higher risk of gingival recession, dehiscence, and fenestration, especially when teeth are moved beyond their bony envelope.
During the mixed dentition phase, significant changes occur in both soft and hard tissues as part of the normal development of the stomatognathic system. These changes may affect tooth position and the stability of periodontal tissues, making evaluation of the gingival phenotype particularly relevant in pediatric patients. Mandibular incisors have been identified as the most vulnerable teeth for the development of labial gingival recession following orthodontic treatment.
Interceptive orthodontics aims to prevent or limit the severity of malocclusions at an early age. Early identification of a thin gingival phenotype enables clinicians to consider preventive measures-such as restricting tooth movement within biological limits or planning soft tissue augmentation procedures prior to critical orthodontic movements.
Genetic, anatomical, and functional factors influence the gingival response to orthodontic forces; therefore, personalized orthodontic planning that integrates periodontal assessment is essential for long-term treatment outcomes and periodontal health.
Gap in the Literature
No studies currently available in the literature have evaluated the relationship between the severity of dental crowding and the periodontal phenotype in pediatric patients. Data in the adult population remain inconsistent: Kaya et al. found no correlation between gingival phenotype and skeletal malocclusion in adults, while Kong et al. reported an association between a thin biotype and skeletal Class I and III, specifically at the left mandibular central incisor, as well as a significant association between thin phenotype and normodivergent and hypodivergent patterns. No predictive model currently exists for identifying patients at periodontal risk due to severe crowding in childhood.
Study Objectives
Primary objective: To assess the periodontal phenotype in pediatric patients at different stages of dental transition (early, middle, and late mixed dentition) and to investigate the association between a thin periodontal biotype and severe dental crowding.
Secondary objectives: To evaluate the distribution of periodontal phenotype subtypes across different stages of dental development; to identify potential clinical predictors of a thin phenotype in the pediatric population; and to provide preliminary data for future longitudinal studies on periodontal outcomes in patients undergoing interceptive orthodontic treatment.
Study Design
This is a cross-sectional, observational study conducted in pediatric patients presenting for routine dental examination. Periodontal phenotype will be assessed using validated clinical and/or ultrasound-based methods. Dental crowding will be classified according to standard indices. Data on dental development stage, skeletal pattern, and relevant clinical variables will be collected. Statistical analyses will include descriptive statistics and appropriate tests of association.
323 studies on the registry are indexed under Malocclusion; 85 are open to participants now.
This study's planned enrollment of 180 is above the median of 63 across 74 observational studies indexed under Malocclusion.
Browse Malocclusion studies →Fondazione Policlinico Universitario Agostino Gemelli IRCCS is the lead sponsor of 952 studies on the registry; 541 are open to participants now.
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Pediatric population of both sexes, aged between 5 and 16 years.
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Group 1 (Primary Dentition): Presence in the mandibular arch of deciduous teeth from canine to canine. Group 2 (Early Mixed Dentition): Presence in the mandibular arch of at least two permanent mandibular incisors, fully erupted (incisal edge at occlusal level) or partially erupted (≥50% of the crown), with no clinical attachment loss, and healthy gingiva or mild gingivitis (Gingival Index, GI ≤ 1). Group 3 (Late Mixed Dentition): Presence in the mandibular arch of all four permanent mandibular incisors fully erupted (incisal edge at occlusal level), with no clinical attachment loss, and healthy gingiva or mild gingivitis (GI ≤
1). Group 4 (Permanent Dentition): Presence in the mandibular arch of all four permanent mandibular incisors fully erupted (incisal edge at occlusal level), with no clinical attachment loss, and healthy gingiva or mild gingivitis (GI ≤ 1).
Exclusion Criteria:
Patient-related:
Tooth-related:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
This group includes children who still have all their primary (baby) teeth, with no eruption of permanent teeth. Typically, this stage ranges from approximately 2 to 6 years of age.
Other: Orthodontic and periodontal analysis
This group includes children in the initial phase of tooth transition, where the first permanent molars and incisors have erupted while primary teeth are still present. This stage generally occurs between 6 and 8 years of age.
Other: Orthodontic and periodontal analysis
This group consists of children in the later phase of dental transition, when canines and premolars begin to replace primary teeth. It usually occurs between 9 and 12 years of age.
Other: Orthodontic and periodontal analysis
This group includes adolescents who have completed the transition and have all or nearly all of their permanent teeth, excluding third molars (wisdom teeth). This stage typically begins around age 12 and up.
Other: Orthodontic and periodontal analysis
Intraoral digital impression aimed at orthodontic analysis and periodontal evaluation using a dedicated periodontal probe, as part of the routine dental examination.
Gingival Phenotype in Pediatric Patients Across Dentition Stages
Assessment of gingival phenotype in pediatric patients categorized by dentition stage: Group 1: Primary dentition Group 2: Early mixed dentition Group 3: Late mixed dentition Group 4: Permanent dentition Gingival phenotype will be classified as thin or thick based on standardized clinical criteria. Measurement Tool: Transgingival probing using a periodontal probe (probe transparency method) Unit of Measure: Categorical variable: Thin vs. Thick gingival phenotype Gingival thickness measured in millimeters (mm), if quantitative assessment is used.
Time frame: 24 months (18 months data collection, 12 months data processing and analysis)
Comparison of Crowding Indices and Periodontal Biotype
Quantitative assessment of dental crowding in pediatric patients across the four dentition groups. Measurement Tool: Little's Irregularity Index and/or arch length-tooth size discrepancy measured on digital models Unit of Measure: Millimeters (mm) of crowding or Index score (numeric value, continuous)
Time frame: From ethics committee approval through 24 months (18 months data collection, 12 months data processing and analysis)
Plan to share: No
No publications or documents are linked to this record.
Started Dec 2025 (actual). Primary completion is estimated for Oct 2026, 10 months after the start.
Of 32 observational studies under Malocclusion, half reached primary completion within 25 months of starting (the median), counting those still running; a quarter within 12 and three quarters within 46. This study's planned 10 months is below that.
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