{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T11:18:57Z","timestamp":1780399137985,"version":"3.54.1"},"reference-count":26,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T00:00:00Z","timestamp":1780358400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Dentistry Journal"],"abstract":"<jats:p>Background: Interceptive orthodontic treatment during mixed dentition aims to reduce malocclusion complexity and improve occlusal development. Although Invisalign\u00ae First was introduced for Phase I therapy in growing patients, evidence regarding longitudinal occlusal outcomes and maintenance during dental development remains limited. This study described longitudinal changes in occlusal outcomes and case complexity using standardized indices in moderate-to-severe malocclusions. Methods: Records of children in early mixed dentition treated with Invisalign\u00ae First between 2019 and 2025 were retrospectively analyzed. The full sample comprised 55 patients with complete digital occlusal records at baseline (T0), post-treatment (T1), and after a minimum 18-month follow-up period (T2), enabling longitudinal assessment using the Peer Assessment Rating (PAR) Index. All patients underwent baseline cephalometric assessment for diagnosis and treatment planning. A nested subsample of 47 patients with complete paired T0-T1 cephalometric records was additionally evaluated using a literature-based mixed dentition complexity framework adapted from Align\u00ae clinical recommendations. Nonparametric tests (Wilcoxon and Friedman) were applied (\u03b1 = 0.05). Results: Median PAR scores decreased from 22.0 (IQR 17.0\u201330.0) at T0 to 6.0 (IQR 1.0\u20138.0) at T1 and 7.0 (IQR 2.0\u201310.0) at T2, with no significant difference between T1 and T2 (p = 0.546). In the cephalometric subsample, global complexity decreased by 79.49 \u00b1 22.43%, with correction rates exceeding 85% for dentoalveolar objectives and reaching 100% for posterior crossbite and open bite. Skeletal and sagittal molar components showed more limited improvement. Conclusions: Interceptive treatment with Invisalign\u00ae First showed longitudinal reductions in occlusal complexity and high dentoalveolar correction rates, with maintenance of occlusal outcomes during follow-up as patients transitioned from mixed to permanent dentition. These findings should be interpreted as descriptive longitudinal observations within a non-controlled design.<\/jats:p>","DOI":"10.3390\/dj14060338","type":"journal-article","created":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T10:14:57Z","timestamp":1780395297000},"page":"338","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Longitudinal Changes in Occlusal Outcomes and Case Complexity with Invisalign\u00ae First in Early Mixed Dentition"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0012-6626","authenticated-orcid":false,"given":"Teresa","family":"Pinho","sequence":"first","affiliation":[{"name":"UNIPRO\u2014Oral Pathology and Rehabilitation Research Unit, University Institute of Health Science (IUCS\u2014CESPU), 4585-116 Gandra, Portugal"},{"name":"Unit for Multidisciplinary Research in Biomedicine (UMIB), School of Medicine and Biomedical Sciences (ICBAS), University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-3805-4614","authenticated-orcid":false,"given":"Martim","family":"Novais","sequence":"additional","affiliation":[{"name":"UNIPRO\u2014Oral Pathology and Rehabilitation Research Unit, University Institute of Health Science (IUCS\u2014CESPU), 4585-116 Gandra, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7950-0053","authenticated-orcid":false,"given":"Maria dos Prazeres","family":"Gon\u00e7alves","sequence":"additional","affiliation":[{"name":"Associate Laboratory I4HB, Institute for Health and Bioeconomy, University Institute of Health Sciences (IUCS\u2014CESPU), 4585-116 Gandra, Portugal"},{"name":"UCIBIO\u2014Applied Molecular Biosciences Unit, Translational Toxicology Research Laboratory, University Institute of Health Sciences (1H-TOXRUN, IUCS\u2014CESPU), 4585-116 Gandra, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"371","DOI":"10.1007\/s00056-002-0210-6","article-title":"A Study of Children with Unilateral Posterior Crossbite, Treated and Untreated, in the Deciduous Dentition","volume":"63","author":"Thilander","year":"2002","journal-title":"J. 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